100 Years of Progress in Polar Meteorologypolarmet.osu.edu/PMG_publications/walsh_bromwich... ·...
Transcript of 100 Years of Progress in Polar Meteorologypolarmet.osu.edu/PMG_publications/walsh_bromwich... ·...
Chapter 21
100 Years of Progress in Polar Meteorology
JOHN E WALSH
International Arctic Research Center University of Alaska Fairbanks Fairbanks Alaska
DAVID H BROMWICH
Byrd Polar and Climate Research Center The Ohio State University Columbus Ohio
JAMES E OVERLAND
NOAA Pacific Marine Environmental Laboratory Seattle Washington
MARK C SERREZE
National Snow and Ice Data Center University of Colorado Boulder Boulder Colorado
KEVIN R WOOD
Joint Institute for the Study of the Atmosphere and Oceans University of Washington Seattle Washington
ABSTRACT
The polar regions present several unique challenges to meteorology including remoteness and a harsh en-
vironment We summarize the evolution of polar meteorology in both hemispheres beginning with measure-
ments made during early expeditions and concluding with the recent decades in which polar meteorology has
been central to global challenges such as the ozone hole weather prediction and climate change Whereas the
1800s and early 1900s provided data from expeditions and only a few subarctic stations the past 100 years have
seen great advances in the observational network and corresponding understanding of the meteorology of the
polar regions For example a persistent view in the early twentieth century was of an Arctic Ocean dominated
by a permanent high pressure cell a glacial anticyclone With increased observations by the 1950s it became
apparent that while anticyclones are a common feature of theArctic circulation cyclones are frequent andmay
be found anywhere in the Arctic Technology has benefited polar meteorology through advances in in-
strumentation especially autonomously operated instruments Moreover satellite remote sensing and com-
puter models revolutionized polar meteorology We highlight the four International Polar Years and several
high-latitude field programs of recent decades We also note outstanding challenges which include un-
derstanding of the role of the Arctic in variations of midlatitude weather and climate the ability to model
surface energy exchanges over a changing Arctic Ocean assessments of ongoing and future trends in extreme
events in polar regions and the role of internal variability in multiyear-to-decadal variations of polar climate
1 Introduction
The development of polar meteorology has faced
unique challenges including the remoteness and the harsh
environments of the Arctic and Antarctic Whereas the
1800s and early 1900s provided data from expeditions and
only a few subarctic stations the past 100 years have seen
an acceleration of observations and understanding of
polar meteorology In addition to the establishment of
new observing stations technology has benefitted polar
meteorology through advances in instrumentation es-
pecially autonomously operated instrumentsMoreover
spatial coverage from satellites and computer models rev-
olutionized polar meteorology which has emerged over
the past half century as a widely recognized subdiscipline
of atmospheric and climate science In this review weCorresponding author John E Walsh jewalshalaskaedu
CHAPTER 21 WAL SH ET AL 211
DOI 101175AMSMONOGRAPHS-D-18-00031
2018 American Meteorological Society For information regarding reuse of this content and general copyright information consult the AMS CopyrightPolicy (wwwametsocorgPUBSReuseLicenses)
summarize the evolution of polar meteorology in both
hemispheres beginning with measurements made dur-
ing early expeditions and concluding with the recent
decades in which polar meteorology has been central
to global challenges such as the Antarctic ozone hole
weather prediction and climate change
2 Review of the pre-1919 period (before theestablishment of the American MeteorologicalSociety)
The development of polar meteorology in the nine-
teenth century is inextricably linked to the engines of
commerce territorial expansion and geographic explo-
ration From an American perspective these begin with
theUS South Seas Exploring Expedition (also known as
theWilkes Expedition or simply theUS Ex Ex) during
1838ndash42 (Wilkes 1845ab) followed by the lesser-known
US North Pacific Exploring and Surveying Expedition
(RinggoldndashRodgers Expedition) of 1853ndash56 (Ringgold
and Rodgers 1950 US National Archives 1964) both
US Navy expeditions TheUS Navy often with private
support contributed to the search for the missing British
expedition of Sir JohnFranklin in theArctic islands north
of Canada and to a number of other early explorations
along the west coast of Greenland These efforts added
to early knowledge of Arctic meteorology mainly by
providing observations (eg Kane 1854 Kane and Schot
1859 Tyson and Howgate 1879 Bessels 1876) for com-
parison with modern observational data and also de-
scriptions of the atmospheric (as well as ice and ocean)
phenomena they encountered Steep inversions and as-
sociated mirages ice fog sea ice ridges and leads and
floating ice islands are examples The first documented
measurements of surface-based inversions were actually
made by measuring temperatures from the lsquolsquocrowrsquos nestrsquorsquo
at 32 m above sea level on Nansenrsquos Fram expedition
(Palo et al 2017) The Army Signal Service the Coast
Survey and the Smithsonian Institution frequently sup-
ported observers supplied meteorological instruments
and provided expert data reduction and publishing as-
sistance to these endeavors (eg Abbe 1893)
The Wilkes Expedition reached Antarctica but there
were no follow-up scientific expeditions to this region
organized in the United States until the first of the Byrd
expeditions in 1928 (Riffenburgh 2006) In the Arctic
however the development of the whaling industry in the
Chukchi and Beaufort Seas beginning in 1848 the pur-
chase of Alaska from Russia in 1867 and the rise of
collaborative scientific exploration of the polar regions
as demonstrated by the landmark first International
Polar Year (IPY 1881ndash84) provided steady impetus for
exploration and research in the far north
The ill-fated 1879 expedition of the USS Jeannette
which set out to reach the North Pole by following a hy-
pothetical lsquolsquothermometric gatewayrsquorsquo through Bering Strait
to an open polar sea (Bent 1872 Hayes 1867) was perhaps
the last to be motivated in large part by speculative geo-
graphical notions about the Arctic including the possi-
bility of an ice-free polar ocean Today the Jeannette
expedition or more directly the part of its wreck that
turned up years later in Greenland is known as an in-
spiration for Fridtjof Nansenrsquos attempt to drift with the
sea ice across the North Pole in the Fram (Nansen 1898)
While expeditions like those carriedoutwith the Jeannette
and the Fram certainly pressed the frontier of discoverymdash
often at a high costmdashand produced extremely valuable
results the underlying story of scientific progress is per-
haps best revealed in the sustained even routine work to
measure describe and map the lands and oceans their
resources and the weather and climate Innovation was a
key factor from the beginning as new tools for observing
the deep sea and the upper atmosphere were constantly
being developed along with more capable ships (and
later aircraft) for operation in harsh polar conditions The
value to science of the vast archive of data that was dili-
gently collected by hundreds of people over these years is
still being realized
a Early investigations of weather and ice
The earliest sustained and systematic investigations of
the weather climate and oceanography of the Arctic by
the United States came with the Alaska Purchase (https
wwwlocgovrrprogrambibourdocsAlaskahtml) The
US Coast Survey and the Revenue Cutter Service (pre-
decessor of the US Coast Guard) began with an initial
reconnaissance in 1867 with a view toward collecting in-
formation necessary for the production of navigational
charts and for theCoast Pilot ofAlaska (USCoast Survey
1869) Starting in 1880 the Revenue Cutter ServiceCoast
Guard made annual summer cruises to the northern Be-
ring and Chukchi Seas and in the process collected a
nearly unbroken series of marine-meteorological and sea
ice observations that extends to the present day (Fig 21-1)
The US Navyrsquos Bureau of Navigation also issued
Findlayrsquos (1869)Directory for the Behringrsquos Sea and Coast
of Alaska a compendium of previously published infor-
mation about the region including a review of weather
and sea ice conditions in the Arctic recorded by earlier
explorers over the previous 100 years back to Cook and
Clerkersquos voyages in 1778 and 1779 (Beaglehole 1967)
At the same time the US Army garrisoned Sitka
(New Archangelsk) and a few other former Russian
outposts forming the beginning of the station network in
Alaska that would later be developed by the Army Signal
Service (as the first official weather agency then known as
212 METEOROLOG ICAL MONOGRAPHS VOLUME 59
the Division of Telegrams and Reports for the Benefit of
Commerce and Agriculture) A break in operations oc-
curred in 1886 and all Signal Service work in Alaska was
abandoned the following year (Henry 1898) In 1890 the
meteorological duties of the Signal Service were trans-
ferred to the US Weather Bureau newly organized as a
civilian agencywithin theUSDepartment ofAgriculture
The Weather Bureau began to rebuild the Alaska station
network in the late 1890s with coverage of the coasts of
Alaska beginning to fill in by 1920 marked by the rees-
tablishment of a station at Point Barrow (Weather Bureau
1925) initially occupied by the Signal Service for the first
IPY in 1881 The development of the station network
between 1867 and 1921 is shown in Fig 21-2 Observations
from these stations have become an important part of the
record used to understand long-term climate trendsmdashin-
sights that depend on data lsquolsquosince record-keeping beganrsquorsquo
The first thorough synthesis studies of the meteorol-
ogy and oceanography of the Pacific Arctic to be pro-
duced in the nineteenth century were made by William
Dall of the US Coast Survey These were Coast Pilot of
Alaska Appendix I Meteorology (Dall 1879) and Report
on the Currents and Temperatures of Bering Sea and the
Adjacent Waters published as Appendix 16 of the Annual
Report of the Superintendent of the US Coast and Geo-
detic Survey (Dall 1882) Both are exhaustive examinations
of the data available from earlier times especially from
Russian and British sources dating back to the 1820s and
included new observations collected by the Coast Survey
the Medical Department of the Army and the Signal Ser-
vice Information was also compiled from whaling ship
captains and other sources both published and from origi-
nal logbooks Dall assembled and published in Coast Pilot
of Alaska Appendix I Meteorology a bibliography and list
of charts containing more than 4000 titles
For Coast Pilot of Alaska Meteorology (1879) Dall
produced the first set of synoptic-scale charts of mean
annual and monthly barometric pressure for the Pacific
Arctic region which provided a reasonable character-
ization of the Aleutian low Dall (1882) notes
The most striking feature presented by the curves ofmean annual pressure is a region of depressed barometerextending fromUnimakPass toKadiak [Kodiak] Island overwhich area so far as the material permits of generalizationa mean pressure is exerted of only 2965 inches This areaof depression which I shall term the Kadiak area was first
FIG 21-1 The USCGC (Coast Guard Cutter) Bearmoored to sea ice in 1918 The Bear was initially purchased by the Navy for the Greely
Relief Expedition in 1884 (Schley 1887) and subsequently served with the Revenue Cutter ServiceCoast Guard in Alaska until 1928 then on
Admiral Byrdrsquos expeditions to Antarctica from 1933 to 1940 and finally with the Navy on the Greenland Patrol during World War II It was
decommissioned for the last time in 1944 (The photograph was provided by the Coast Guard Museum Northwest in Seattle Washington)
CHAPTER 21 WAL SH ET AL 213
FIG 21-2 The meteorological station network developed by the US Army Signal Service and the Weather Bureau in Alaska 1867ndash
1921 The IPY stations at Fort Conger on Ellesmere Island and at Fort Chimo (Kuujjuaq Nunavit) are also included The IPY period is
marked by gray lines The collapse of the Signal Service network in 1887 is apparent
214 METEOROLOG ICAL MONOGRAPHS VOLUME 59
indicated by Mr Ferrel (1875) but from incompleteness ofdata in his possession it was located somewhat too far north
Ferrel at the time with the Coast Survey and subse-
quently with the Signal Service outlined the general cir-
culation of the atmosphere based on physical principles
(Abbe 1892) including the Coriolis force well in advance
of work by Teisserenc de Bort (1883) Exner (1913)
Walker (1923) and others Figure 21-3 shows theNorthern
Hemisphere sea level pressure and prevailing winds for
January from his analysis Dallrsquos (1879) regional map for
the same month (Fig 21-4 top panel) shows a more ac-
curate placement of theAleutian low based on station data
that were unavailable to Ferrel and it provides an example
FIG 21-3 Ferrelrsquos map in Meteorological Researches for the Use of the Coast Pilot (Ferrel 1875) lsquolsquoshowing by isobaric lines the mean
pressure of the atmosphere for January in millimeters reduced to the gravity of the parallel of 458 and by arrows the prevailing directions
of the wind for the Northern Hemispherersquorsquo Although the center of action in the Pacific (Aleutian low) is placed too far north as his
colleague Dall noted the resemblance to modern maps is unmistakable (see eg Hurrell et al 2003 their Figs 1 and 2)
CHAPTER 21 WAL SH ET AL 215
of the characteristic westndasheast split of the Aleutian low
Simultaneous international observations supported this
interpretation (egBulletin of InternationalMeteorological
Observations 1875ndash87 from the US Army Signal Office)
It is now understood that in winter the positions of the one
versus two centers of the Aleutian low are more important
with respect to influence on the Bering Sea environment
than its central pressure (eg Rodionov et al 2005)
Dall also documented general outlines of other im-
portant features of the regional climate in the areas of
meteorology oceanography and biology These include
mean annual and monthly air temperature patterns and
prevailing winds ocean currents and sea surface tem-
peratures the summer distribution of sea ice winds and
temperatures over boreal and tundra regions (Fig 21-4
bottom panel) and associated plants and animals The
FIG 21-4 (top) Dallrsquos (1879) regional map of barometric pressure in January showing a split Aleutian low (referred to by Dall as the
Kadiak area in general with the Kamchatka area appearing in the case of split development) Dall recognized that the lack of data from
the western Aleutians left this question ambiguous but today it is seen to be the correct interpretation (eg Rodionov et al 2005)
(bottom) Dallrsquos (1879) map of summer sea surface isotherms and main ocean currents The average extent of sea ice in summer is also
shown and is generally consistent with what is known about ice distribution in the early satellite era and before (eg Danske
Meteorologiske Institut 1900ndash1939 1946ndash1956 US Hydrographic Office 1946)
216 METEOROLOG ICAL MONOGRAPHS VOLUME 59
oceanography of the Bering Sea is dealt with in more
detail in Dallrsquos subsequent work
In his Report on the Currents and Temperatures of Be-
ring Sea and the Adjacent Waters Dall (1882) turned his
attention to questions that are still relevant today What
ocean currents pass between the Pacific Ocean into the
Bering Sea and thence into the Arctic by way of Bering
Strait or from the Arctic to the south What are the
temperatures of these currents and what effect do they
have on the climate including the distribution of sea ice
As he did in his work on meteorology for the Coast Pilot
Dall scoured the literature (and primary sources) from
around the world for data and collected new oceano-
graphic observations as well in his role as assistant-in-
charge of the Coast Survey vessels Yukon and Humbolt
Of particular note is the hydrographic transect of the
Bering Strait completed in 1880 likely the first ever ob-
tained (Fig 21-5) In part the motivation for the transect
was to test the hypothesis that a branch of the warmKuro
Siwo (Kuroshio) passed through Bering Strait creating
a lsquolsquothermometric gatewayrsquorsquo (Bent 1872) that the USS
Jeannette would have followed into the Arctic At the
same time the USRC (Revenue Cutter) Corwin was
searching the area around Wrangel Island for signs of the
missing ship last seen the previous September in the ice
near Herald Island (Hooper 1881) Unbeknownst to both
Dall and Captain Hooper of the Corwin Commander De
Long and the officers of the Jeannette had already ex-
ploded two of the prevailing myths that inspired their
expedition there was no such thing as a thermometric
gateway andWrangel Land was an island and not a large
landmass extending across the Arctic (De Long 1884)
Dallrsquos hydrographic transect combined with the gen-
eral survey of the region yielded a number of particular
insights He found that the current through the Bering
Strait is mainly to the north although reversible by the
wind and that the northward flow is around 1 ft s21mdash
corresponding to a total flow of 42289425 ft3 s21 (12 Sv
1 Sv [ 106 m3 s21) which corresponds well to modern
measurements (eg Woodgate et al 2005) The tempera-
ture structure resolved by theYukon transect in September
shows the warm Alaska Coastal Current (ACC) on the
FIG 21-5 (top)Map of the Bering Strait region showing surface isotherms and sea ice observed by the US Coast Survey schoonerYukon
in AugustSeptember 1880 and (bottom) the hydrographic section obtained on 5 September 1880 (Dall 1882)
CHAPTER 21 WAL SH ET AL 217
eastern side of the strait and the cold Siberian Coastal
Current (Weingartner et al 1999) on the western side The
presence of sea ice at East Cape and southward seems
unusual when compared with recent data but this was
once a common occurrence (eg Danske Meteorologiske
Institut 1900ndash1939 1946ndash1956)Otherwise the temperature
range found by Dall is fairly typical As to the source of
ocean heat present in the region Dall observed that it was
primarily due to local solar radiation rather than to heat
transported into the area from the Pacific Ocean as sug-
gested by Bent (1872) a result consistent with the recent
findings by Timmermans et al (2018)
b The first International Polar Year
The first IPY is notable as the first attempt to extend
a wide meteorological network into the Arctic and
to collect simultaneous observations with similar well-
calibrated instruments and methods The first IPY was
inspired by the Austro-Hungarian naval officer and sci-
entist Karl Weyprecht (Wood and Overland 2006) The
idea for a coordinated international expedition arose from
his experience as co-commander of the Austro-Hungarian
Polar Expedition of 1872ndash74 After returning home he
reflected on the value of the thousands of meteorological
measurements made during the expedition and noted
But whatever interest all these observations may possessthey do not possess that scientific value even supported bya long column of figures which under other circumstancesmight have been the case They only furnish us with apicture of the extreme effects of the forces of Nature in theArctic regions but they leave us completely in the darkwith respect to their causes (Weyprecht 1875)
To answer that question he understood that large-scale
synchronous data collection was required just as it is now
Weyprechtrsquos address to a meeting of German naturalists
and physicians in 1875 included an enduring assessment
lsquolsquoThe entire meteorology of our day rests upon compari-
son All the successes of which it can boastmdashthe laws of
storms the theories of windsmdashare the result of synchro-
nous observationsrsquorsquo (Wood and Overland 2006)
The Second International Meteorological Congress
held inRome in 1879 supportedWeyprechtrsquos conception
of a coordinated international polar research effort and
established a commission to put it into effect It was to be
as Abbe (1893) described it lsquolsquoa simultaneous invasion of
the polar regions from all sidesrsquorsquo International partici-
pation was invited and in due course 11 nations estab-
lished 14 polar research stations 12 in the Arctic and two
in the subantarctic A number of auxiliary stations were
also established including several in Alaska Participa-
tion by the United States was the responsibility of the
Army Signal Service which established two stations one
at Lady Franklin Bay Ellesmere Island and another at
Point Barrow Alaska Lieutenant Adolphus W Greely
(an early member of the American Meteorological So-
ciety) took command of the former expedition and
Lieutenant Patrick Henry Ray commanded the latter
The results of the first IPY were mixed Lieutenant
Greelyrsquos expedition to Lady Franklin Bay was marred
by the loss of all but seven members to deprivation and
other causes Abbe (1893) stated that
the large volumes and results of the two Signal Service in-ternational polar stations as well as the work of the Polarisand Florence expeditions have contributed not a little toadvance our knowledge of the immense country lying to thenorth of the United States in fact the great importance ofthis work becomes more and more evident as other gov-ernments publish their own contributions to this year ofcooperative research and thus enable us to take a compre-hensive survey of the atmospheric conditions at that time
The full publication of the synchronous observations
unfortunately took 25 yearsmdashit was not completed until
1910 and the data were never analyzed all together as
Weyprecht had envisioned
The meteorological observations of the first IPY were
recently transcribed digitized and assimilated by modern
retrospective analysis (reanalysis) systems (eg Compo
et al 2011) and in this sense have finally fulfilled their in-
tended purpose (Wood and Overland 2006) The greater
legacy of the first IPY may be that its successful demon-
stration of international collaboration in polar science
carried on to three subsequent iterations the second IPY
of 1932ndash33 the International Geophysical Year (or third
IPY) of 1957ndash58 (IGY) and the recent IPY of 2007ndash09
c Arctic work of the Weather Bureau
The Alaska Section of the Weather Bureau was offi-
cially started in 1898 with the establishment of the Climate
and Crop Service and set up of a first-class weather station
at Sitka under the direction ofHLBall (Ball 1898) From
the end of the Signal Service years until the 1920s much of
the meteorological data for the region was collected by
volunteer observers Aside from the Sitka station 10 new
subsidiary stations were also expected to be operated by
volunteers Henry (1898) also noted lsquolsquoIt is hoped that
those to whom instruments have been issued from time to
time in previous years will also revive their interests and
report to [Ball]rsquorsquo Of 18 volunteer stations listed by Henry
that were issued instruments by the Weather Bureau the
most successful were located at Coal Harbor (1889ndash1911)
and Killisnoo (1881ndash1910) Other efforts were not as suc-
cessful Instruments sent to observers in the Northwest
Territories (Canada) were seized and in another case the
observer a missionary was murdered and the records
218 METEOROLOG ICAL MONOGRAPHS VOLUME 59
were lost Further development by theWeather Bureau in
Alaska in the early twentieth century was spurred by
economic development around the gold rush and the es-
tablishment of radio and cable communications (Jessup
2007) as well as the increased need for aviation weather
services beginning in the 1920s (see Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
The Weather Bureaursquos further contributions to polar
meteorology followed a similar pattern as in previous
years although on very small scale Between 1893 and
1902 Evelyn Briggs Baldwin aWeather Bureau observer
took part in three privately supported Arctic adventures
Pearyrsquos North Greenland Expedition in 1893ndash94 the
SecondWellmanExpedition to Franz Josef Land in 1898ndash
99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02
Thiswould be the only polar activity directly related to the
Weather Bureau until the 1920s (Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
d Early Antarctic observations
While efforts by the United States were focused on
the Arctic important work in the Antarctic was being
carried out especially by other nations Major meteo-
rological studies in Antarctica commenced with two
historical expeditions The first was in conjunction with
Robert F Scottrsquos attempt (1910ndash13) to be the first to
reach the South (geographic) Pole Scottrsquos Party peri-
shed in 1912 on the Ross Ice Shelf after having arrived at
the Pole 1 month after Roald Amundsen The role
played by weather in this tragedy remains controversial
to this day (Solomon 2001 Fogt et al 2017) Detailed
meteorological observations were collected during
1911ndash12 at the base location of Cape Evans on Ross
Island by George C Simpson who later became Di-
rector General of theUnited KingdomrsquosMeteorological
Office The reporting and analysis of the observations
were delayed byWorldWar I but appeared in a series of
volumes published in India (Simpson 1919 1921 1923)
Important was that the analysis suggested the origin of
lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)
which became a prime motivation for the establishment
of Byrd Station (808S 1208W) during the IGY (1957)
Although the observations have not been continuous
the early observations from the Byrd Station location
have enabled recent studies to demonstrate large annual
temperature increases since the IGY 228 6 138C from
1958 to 2010 (Bromwich et al 2013 2014)
The second expedition of major meteorological im-
portance was led by Douglas Mawson (the Australasian
Antarctic Expedition 1911ndash14) whose experiences were
outlined in a well-known book entitled The Home of the
Blizzard (Mawson 1915) In an ironic twist of events
the party came ashore at Cape Denison (678S 14278E)
because there was open water right to the coast providing
easy access for their ship The meteorological records
from 1912ndash13 revealed the most intense sustained wind
regime on Earth (Madigan 1929) The anemometer was
recalibrated because of doubts about the extreme condi-
tions experienced and it now appears that the revision
was overly conservative The uncorrected records reveal
an annual average wind speed of 22 m s21 with over 60
of all hourly wind speed reports falling in the range of 15ndash
30 m s21 (Parish and Walker 2006) The easy summer ac-
cess to the coast was caused by the intense katabatic winds
blowing the sea ice offshore to create coastal polynyas
(MoralesMaqueda et al 2004) and therefore choosing this
location turned out to be an unfortunate choice in retro-
spect A similar sequence of extreme katabatic wind events
was experienced in 1912 by a satellite party of the Scott
Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)
e A modern renaissance in historical climatology
The advent of sparse-input reanalysis and reanalysis-
forcedmodeling and reconstruction techniques in recent
years has brought new interest in data that were col-
lected in the past but never integrated into modern
large-scale datasets [eg the International Compre-
hensive OceanndashAtmosphere Data Set (ICOADS) the
International Surface Pressure Databank (ISPD)] A
surprisingly large amount of marine-meteorological and
sea ice data collected in the polar regions by the US
Navy Revenue Cutter ServiceCoast Guard and other
federal vessels since the 1880s has never been extracted
from primary sources and compiled This deficit how-
ever is steadily being reduced through collaborative
data recovery projects organized under the Atmospheric
Circulation Reconstructions over the Earth (ACRE) ini-
tiative (Allan et al 2011) and with support from citizen-
scientists participating in Old Weather (httpwww
oldweatherorg) and similar projects (Freeman et al 2016)
Of particular note in this regard are the sea ice ob-
servations collected in the nineteenth and early twenti-
eth century Some of these data were used in a few early
studies (eg Page 1900 Simpson 1890) and from 1900
to 1939 as occasional contributions to the Danish Me-
teorological Institutersquos annual publication State of the
Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash
1939 1946ndash1956) This publication remains a primary
source of sea ice data for the period in modern datasets for
example the Hadley Centrersquos Sea Ice and Sea Surface
Temperature Dataset version 2 (Titchner and Rayner
2014 Walsh and Chapman 2001) and reanalyses that as-
similate ice information [eg the European Centre for
Medium-Range Weather Forecasts (ECMWF) twentieth
century reanalysis (ERA-20C) Poli et al 2016] Reanalyses
CHAPTER 21 WAL SH ET AL 219
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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Cohen J and Coauthors 2014 Recent Arctic amplification and
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JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
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Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
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Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
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ice in the Arctic seas) I Kommission Hos GEC Gad
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de Boer G W Chapman J Kay B Medeiros M D Shupe
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De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
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Dorsey H G Jr 1945 Some meteorological aspects of the
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Douglass A P Newman and S Solomon 2014 The Antarctic
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DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
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R Osinski and A Roberts 2016 Winter atmospheric buoy-
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around southeasternGreenland in theRegionalArctic System
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Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
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English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
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Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
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315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
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1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
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mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
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Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Summer snowfall impact on the Greenland Ice Sheet Cryo-
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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North America Polar Sci 16 1ndash9 httpsdoiorg101016
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Page J 1900 Ice and ice movements in Bering Sea during the
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Palmeacuten E 1951 The role of atmospheric disturbances in the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
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Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
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Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
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Rodionov S N J E Overland and N A Bond 2005 The
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
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Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
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Screen J A and I Simmonds 2010 The central role of diminishing
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
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Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
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Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
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Taylor P C M Cai A Hu J Meehl W Washington and G J
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Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Thomson A 1948 The growth of meteorological knowledge of
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ThorndikeA S andRColony 1981ArcticOceanBuoy Program
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Timmermans M L J Toole and R Krishfield 2018Warming of the
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Centre sea ice and sea surface temperature data set version 2
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
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mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
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Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
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JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
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Untersteiner N A S Thorndike D A Rothrock and K L
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CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
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1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
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van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
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THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
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Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
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von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
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for depicting Arctic sea ice variations back to 1850Geogr Rev
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Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
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Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
summarize the evolution of polar meteorology in both
hemispheres beginning with measurements made dur-
ing early expeditions and concluding with the recent
decades in which polar meteorology has been central
to global challenges such as the Antarctic ozone hole
weather prediction and climate change
2 Review of the pre-1919 period (before theestablishment of the American MeteorologicalSociety)
The development of polar meteorology in the nine-
teenth century is inextricably linked to the engines of
commerce territorial expansion and geographic explo-
ration From an American perspective these begin with
theUS South Seas Exploring Expedition (also known as
theWilkes Expedition or simply theUS Ex Ex) during
1838ndash42 (Wilkes 1845ab) followed by the lesser-known
US North Pacific Exploring and Surveying Expedition
(RinggoldndashRodgers Expedition) of 1853ndash56 (Ringgold
and Rodgers 1950 US National Archives 1964) both
US Navy expeditions TheUS Navy often with private
support contributed to the search for the missing British
expedition of Sir JohnFranklin in theArctic islands north
of Canada and to a number of other early explorations
along the west coast of Greenland These efforts added
to early knowledge of Arctic meteorology mainly by
providing observations (eg Kane 1854 Kane and Schot
1859 Tyson and Howgate 1879 Bessels 1876) for com-
parison with modern observational data and also de-
scriptions of the atmospheric (as well as ice and ocean)
phenomena they encountered Steep inversions and as-
sociated mirages ice fog sea ice ridges and leads and
floating ice islands are examples The first documented
measurements of surface-based inversions were actually
made by measuring temperatures from the lsquolsquocrowrsquos nestrsquorsquo
at 32 m above sea level on Nansenrsquos Fram expedition
(Palo et al 2017) The Army Signal Service the Coast
Survey and the Smithsonian Institution frequently sup-
ported observers supplied meteorological instruments
and provided expert data reduction and publishing as-
sistance to these endeavors (eg Abbe 1893)
The Wilkes Expedition reached Antarctica but there
were no follow-up scientific expeditions to this region
organized in the United States until the first of the Byrd
expeditions in 1928 (Riffenburgh 2006) In the Arctic
however the development of the whaling industry in the
Chukchi and Beaufort Seas beginning in 1848 the pur-
chase of Alaska from Russia in 1867 and the rise of
collaborative scientific exploration of the polar regions
as demonstrated by the landmark first International
Polar Year (IPY 1881ndash84) provided steady impetus for
exploration and research in the far north
The ill-fated 1879 expedition of the USS Jeannette
which set out to reach the North Pole by following a hy-
pothetical lsquolsquothermometric gatewayrsquorsquo through Bering Strait
to an open polar sea (Bent 1872 Hayes 1867) was perhaps
the last to be motivated in large part by speculative geo-
graphical notions about the Arctic including the possi-
bility of an ice-free polar ocean Today the Jeannette
expedition or more directly the part of its wreck that
turned up years later in Greenland is known as an in-
spiration for Fridtjof Nansenrsquos attempt to drift with the
sea ice across the North Pole in the Fram (Nansen 1898)
While expeditions like those carriedoutwith the Jeannette
and the Fram certainly pressed the frontier of discoverymdash
often at a high costmdashand produced extremely valuable
results the underlying story of scientific progress is per-
haps best revealed in the sustained even routine work to
measure describe and map the lands and oceans their
resources and the weather and climate Innovation was a
key factor from the beginning as new tools for observing
the deep sea and the upper atmosphere were constantly
being developed along with more capable ships (and
later aircraft) for operation in harsh polar conditions The
value to science of the vast archive of data that was dili-
gently collected by hundreds of people over these years is
still being realized
a Early investigations of weather and ice
The earliest sustained and systematic investigations of
the weather climate and oceanography of the Arctic by
the United States came with the Alaska Purchase (https
wwwlocgovrrprogrambibourdocsAlaskahtml) The
US Coast Survey and the Revenue Cutter Service (pre-
decessor of the US Coast Guard) began with an initial
reconnaissance in 1867 with a view toward collecting in-
formation necessary for the production of navigational
charts and for theCoast Pilot ofAlaska (USCoast Survey
1869) Starting in 1880 the Revenue Cutter ServiceCoast
Guard made annual summer cruises to the northern Be-
ring and Chukchi Seas and in the process collected a
nearly unbroken series of marine-meteorological and sea
ice observations that extends to the present day (Fig 21-1)
The US Navyrsquos Bureau of Navigation also issued
Findlayrsquos (1869)Directory for the Behringrsquos Sea and Coast
of Alaska a compendium of previously published infor-
mation about the region including a review of weather
and sea ice conditions in the Arctic recorded by earlier
explorers over the previous 100 years back to Cook and
Clerkersquos voyages in 1778 and 1779 (Beaglehole 1967)
At the same time the US Army garrisoned Sitka
(New Archangelsk) and a few other former Russian
outposts forming the beginning of the station network in
Alaska that would later be developed by the Army Signal
Service (as the first official weather agency then known as
212 METEOROLOG ICAL MONOGRAPHS VOLUME 59
the Division of Telegrams and Reports for the Benefit of
Commerce and Agriculture) A break in operations oc-
curred in 1886 and all Signal Service work in Alaska was
abandoned the following year (Henry 1898) In 1890 the
meteorological duties of the Signal Service were trans-
ferred to the US Weather Bureau newly organized as a
civilian agencywithin theUSDepartment ofAgriculture
The Weather Bureau began to rebuild the Alaska station
network in the late 1890s with coverage of the coasts of
Alaska beginning to fill in by 1920 marked by the rees-
tablishment of a station at Point Barrow (Weather Bureau
1925) initially occupied by the Signal Service for the first
IPY in 1881 The development of the station network
between 1867 and 1921 is shown in Fig 21-2 Observations
from these stations have become an important part of the
record used to understand long-term climate trendsmdashin-
sights that depend on data lsquolsquosince record-keeping beganrsquorsquo
The first thorough synthesis studies of the meteorol-
ogy and oceanography of the Pacific Arctic to be pro-
duced in the nineteenth century were made by William
Dall of the US Coast Survey These were Coast Pilot of
Alaska Appendix I Meteorology (Dall 1879) and Report
on the Currents and Temperatures of Bering Sea and the
Adjacent Waters published as Appendix 16 of the Annual
Report of the Superintendent of the US Coast and Geo-
detic Survey (Dall 1882) Both are exhaustive examinations
of the data available from earlier times especially from
Russian and British sources dating back to the 1820s and
included new observations collected by the Coast Survey
the Medical Department of the Army and the Signal Ser-
vice Information was also compiled from whaling ship
captains and other sources both published and from origi-
nal logbooks Dall assembled and published in Coast Pilot
of Alaska Appendix I Meteorology a bibliography and list
of charts containing more than 4000 titles
For Coast Pilot of Alaska Meteorology (1879) Dall
produced the first set of synoptic-scale charts of mean
annual and monthly barometric pressure for the Pacific
Arctic region which provided a reasonable character-
ization of the Aleutian low Dall (1882) notes
The most striking feature presented by the curves ofmean annual pressure is a region of depressed barometerextending fromUnimakPass toKadiak [Kodiak] Island overwhich area so far as the material permits of generalizationa mean pressure is exerted of only 2965 inches This areaof depression which I shall term the Kadiak area was first
FIG 21-1 The USCGC (Coast Guard Cutter) Bearmoored to sea ice in 1918 The Bear was initially purchased by the Navy for the Greely
Relief Expedition in 1884 (Schley 1887) and subsequently served with the Revenue Cutter ServiceCoast Guard in Alaska until 1928 then on
Admiral Byrdrsquos expeditions to Antarctica from 1933 to 1940 and finally with the Navy on the Greenland Patrol during World War II It was
decommissioned for the last time in 1944 (The photograph was provided by the Coast Guard Museum Northwest in Seattle Washington)
CHAPTER 21 WAL SH ET AL 213
FIG 21-2 The meteorological station network developed by the US Army Signal Service and the Weather Bureau in Alaska 1867ndash
1921 The IPY stations at Fort Conger on Ellesmere Island and at Fort Chimo (Kuujjuaq Nunavit) are also included The IPY period is
marked by gray lines The collapse of the Signal Service network in 1887 is apparent
214 METEOROLOG ICAL MONOGRAPHS VOLUME 59
indicated by Mr Ferrel (1875) but from incompleteness ofdata in his possession it was located somewhat too far north
Ferrel at the time with the Coast Survey and subse-
quently with the Signal Service outlined the general cir-
culation of the atmosphere based on physical principles
(Abbe 1892) including the Coriolis force well in advance
of work by Teisserenc de Bort (1883) Exner (1913)
Walker (1923) and others Figure 21-3 shows theNorthern
Hemisphere sea level pressure and prevailing winds for
January from his analysis Dallrsquos (1879) regional map for
the same month (Fig 21-4 top panel) shows a more ac-
curate placement of theAleutian low based on station data
that were unavailable to Ferrel and it provides an example
FIG 21-3 Ferrelrsquos map in Meteorological Researches for the Use of the Coast Pilot (Ferrel 1875) lsquolsquoshowing by isobaric lines the mean
pressure of the atmosphere for January in millimeters reduced to the gravity of the parallel of 458 and by arrows the prevailing directions
of the wind for the Northern Hemispherersquorsquo Although the center of action in the Pacific (Aleutian low) is placed too far north as his
colleague Dall noted the resemblance to modern maps is unmistakable (see eg Hurrell et al 2003 their Figs 1 and 2)
CHAPTER 21 WAL SH ET AL 215
of the characteristic westndasheast split of the Aleutian low
Simultaneous international observations supported this
interpretation (egBulletin of InternationalMeteorological
Observations 1875ndash87 from the US Army Signal Office)
It is now understood that in winter the positions of the one
versus two centers of the Aleutian low are more important
with respect to influence on the Bering Sea environment
than its central pressure (eg Rodionov et al 2005)
Dall also documented general outlines of other im-
portant features of the regional climate in the areas of
meteorology oceanography and biology These include
mean annual and monthly air temperature patterns and
prevailing winds ocean currents and sea surface tem-
peratures the summer distribution of sea ice winds and
temperatures over boreal and tundra regions (Fig 21-4
bottom panel) and associated plants and animals The
FIG 21-4 (top) Dallrsquos (1879) regional map of barometric pressure in January showing a split Aleutian low (referred to by Dall as the
Kadiak area in general with the Kamchatka area appearing in the case of split development) Dall recognized that the lack of data from
the western Aleutians left this question ambiguous but today it is seen to be the correct interpretation (eg Rodionov et al 2005)
(bottom) Dallrsquos (1879) map of summer sea surface isotherms and main ocean currents The average extent of sea ice in summer is also
shown and is generally consistent with what is known about ice distribution in the early satellite era and before (eg Danske
Meteorologiske Institut 1900ndash1939 1946ndash1956 US Hydrographic Office 1946)
216 METEOROLOG ICAL MONOGRAPHS VOLUME 59
oceanography of the Bering Sea is dealt with in more
detail in Dallrsquos subsequent work
In his Report on the Currents and Temperatures of Be-
ring Sea and the Adjacent Waters Dall (1882) turned his
attention to questions that are still relevant today What
ocean currents pass between the Pacific Ocean into the
Bering Sea and thence into the Arctic by way of Bering
Strait or from the Arctic to the south What are the
temperatures of these currents and what effect do they
have on the climate including the distribution of sea ice
As he did in his work on meteorology for the Coast Pilot
Dall scoured the literature (and primary sources) from
around the world for data and collected new oceano-
graphic observations as well in his role as assistant-in-
charge of the Coast Survey vessels Yukon and Humbolt
Of particular note is the hydrographic transect of the
Bering Strait completed in 1880 likely the first ever ob-
tained (Fig 21-5) In part the motivation for the transect
was to test the hypothesis that a branch of the warmKuro
Siwo (Kuroshio) passed through Bering Strait creating
a lsquolsquothermometric gatewayrsquorsquo (Bent 1872) that the USS
Jeannette would have followed into the Arctic At the
same time the USRC (Revenue Cutter) Corwin was
searching the area around Wrangel Island for signs of the
missing ship last seen the previous September in the ice
near Herald Island (Hooper 1881) Unbeknownst to both
Dall and Captain Hooper of the Corwin Commander De
Long and the officers of the Jeannette had already ex-
ploded two of the prevailing myths that inspired their
expedition there was no such thing as a thermometric
gateway andWrangel Land was an island and not a large
landmass extending across the Arctic (De Long 1884)
Dallrsquos hydrographic transect combined with the gen-
eral survey of the region yielded a number of particular
insights He found that the current through the Bering
Strait is mainly to the north although reversible by the
wind and that the northward flow is around 1 ft s21mdash
corresponding to a total flow of 42289425 ft3 s21 (12 Sv
1 Sv [ 106 m3 s21) which corresponds well to modern
measurements (eg Woodgate et al 2005) The tempera-
ture structure resolved by theYukon transect in September
shows the warm Alaska Coastal Current (ACC) on the
FIG 21-5 (top)Map of the Bering Strait region showing surface isotherms and sea ice observed by the US Coast Survey schoonerYukon
in AugustSeptember 1880 and (bottom) the hydrographic section obtained on 5 September 1880 (Dall 1882)
CHAPTER 21 WAL SH ET AL 217
eastern side of the strait and the cold Siberian Coastal
Current (Weingartner et al 1999) on the western side The
presence of sea ice at East Cape and southward seems
unusual when compared with recent data but this was
once a common occurrence (eg Danske Meteorologiske
Institut 1900ndash1939 1946ndash1956)Otherwise the temperature
range found by Dall is fairly typical As to the source of
ocean heat present in the region Dall observed that it was
primarily due to local solar radiation rather than to heat
transported into the area from the Pacific Ocean as sug-
gested by Bent (1872) a result consistent with the recent
findings by Timmermans et al (2018)
b The first International Polar Year
The first IPY is notable as the first attempt to extend
a wide meteorological network into the Arctic and
to collect simultaneous observations with similar well-
calibrated instruments and methods The first IPY was
inspired by the Austro-Hungarian naval officer and sci-
entist Karl Weyprecht (Wood and Overland 2006) The
idea for a coordinated international expedition arose from
his experience as co-commander of the Austro-Hungarian
Polar Expedition of 1872ndash74 After returning home he
reflected on the value of the thousands of meteorological
measurements made during the expedition and noted
But whatever interest all these observations may possessthey do not possess that scientific value even supported bya long column of figures which under other circumstancesmight have been the case They only furnish us with apicture of the extreme effects of the forces of Nature in theArctic regions but they leave us completely in the darkwith respect to their causes (Weyprecht 1875)
To answer that question he understood that large-scale
synchronous data collection was required just as it is now
Weyprechtrsquos address to a meeting of German naturalists
and physicians in 1875 included an enduring assessment
lsquolsquoThe entire meteorology of our day rests upon compari-
son All the successes of which it can boastmdashthe laws of
storms the theories of windsmdashare the result of synchro-
nous observationsrsquorsquo (Wood and Overland 2006)
The Second International Meteorological Congress
held inRome in 1879 supportedWeyprechtrsquos conception
of a coordinated international polar research effort and
established a commission to put it into effect It was to be
as Abbe (1893) described it lsquolsquoa simultaneous invasion of
the polar regions from all sidesrsquorsquo International partici-
pation was invited and in due course 11 nations estab-
lished 14 polar research stations 12 in the Arctic and two
in the subantarctic A number of auxiliary stations were
also established including several in Alaska Participa-
tion by the United States was the responsibility of the
Army Signal Service which established two stations one
at Lady Franklin Bay Ellesmere Island and another at
Point Barrow Alaska Lieutenant Adolphus W Greely
(an early member of the American Meteorological So-
ciety) took command of the former expedition and
Lieutenant Patrick Henry Ray commanded the latter
The results of the first IPY were mixed Lieutenant
Greelyrsquos expedition to Lady Franklin Bay was marred
by the loss of all but seven members to deprivation and
other causes Abbe (1893) stated that
the large volumes and results of the two Signal Service in-ternational polar stations as well as the work of the Polarisand Florence expeditions have contributed not a little toadvance our knowledge of the immense country lying to thenorth of the United States in fact the great importance ofthis work becomes more and more evident as other gov-ernments publish their own contributions to this year ofcooperative research and thus enable us to take a compre-hensive survey of the atmospheric conditions at that time
The full publication of the synchronous observations
unfortunately took 25 yearsmdashit was not completed until
1910 and the data were never analyzed all together as
Weyprecht had envisioned
The meteorological observations of the first IPY were
recently transcribed digitized and assimilated by modern
retrospective analysis (reanalysis) systems (eg Compo
et al 2011) and in this sense have finally fulfilled their in-
tended purpose (Wood and Overland 2006) The greater
legacy of the first IPY may be that its successful demon-
stration of international collaboration in polar science
carried on to three subsequent iterations the second IPY
of 1932ndash33 the International Geophysical Year (or third
IPY) of 1957ndash58 (IGY) and the recent IPY of 2007ndash09
c Arctic work of the Weather Bureau
The Alaska Section of the Weather Bureau was offi-
cially started in 1898 with the establishment of the Climate
and Crop Service and set up of a first-class weather station
at Sitka under the direction ofHLBall (Ball 1898) From
the end of the Signal Service years until the 1920s much of
the meteorological data for the region was collected by
volunteer observers Aside from the Sitka station 10 new
subsidiary stations were also expected to be operated by
volunteers Henry (1898) also noted lsquolsquoIt is hoped that
those to whom instruments have been issued from time to
time in previous years will also revive their interests and
report to [Ball]rsquorsquo Of 18 volunteer stations listed by Henry
that were issued instruments by the Weather Bureau the
most successful were located at Coal Harbor (1889ndash1911)
and Killisnoo (1881ndash1910) Other efforts were not as suc-
cessful Instruments sent to observers in the Northwest
Territories (Canada) were seized and in another case the
observer a missionary was murdered and the records
218 METEOROLOG ICAL MONOGRAPHS VOLUME 59
were lost Further development by theWeather Bureau in
Alaska in the early twentieth century was spurred by
economic development around the gold rush and the es-
tablishment of radio and cable communications (Jessup
2007) as well as the increased need for aviation weather
services beginning in the 1920s (see Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
The Weather Bureaursquos further contributions to polar
meteorology followed a similar pattern as in previous
years although on very small scale Between 1893 and
1902 Evelyn Briggs Baldwin aWeather Bureau observer
took part in three privately supported Arctic adventures
Pearyrsquos North Greenland Expedition in 1893ndash94 the
SecondWellmanExpedition to Franz Josef Land in 1898ndash
99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02
Thiswould be the only polar activity directly related to the
Weather Bureau until the 1920s (Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
d Early Antarctic observations
While efforts by the United States were focused on
the Arctic important work in the Antarctic was being
carried out especially by other nations Major meteo-
rological studies in Antarctica commenced with two
historical expeditions The first was in conjunction with
Robert F Scottrsquos attempt (1910ndash13) to be the first to
reach the South (geographic) Pole Scottrsquos Party peri-
shed in 1912 on the Ross Ice Shelf after having arrived at
the Pole 1 month after Roald Amundsen The role
played by weather in this tragedy remains controversial
to this day (Solomon 2001 Fogt et al 2017) Detailed
meteorological observations were collected during
1911ndash12 at the base location of Cape Evans on Ross
Island by George C Simpson who later became Di-
rector General of theUnited KingdomrsquosMeteorological
Office The reporting and analysis of the observations
were delayed byWorldWar I but appeared in a series of
volumes published in India (Simpson 1919 1921 1923)
Important was that the analysis suggested the origin of
lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)
which became a prime motivation for the establishment
of Byrd Station (808S 1208W) during the IGY (1957)
Although the observations have not been continuous
the early observations from the Byrd Station location
have enabled recent studies to demonstrate large annual
temperature increases since the IGY 228 6 138C from
1958 to 2010 (Bromwich et al 2013 2014)
The second expedition of major meteorological im-
portance was led by Douglas Mawson (the Australasian
Antarctic Expedition 1911ndash14) whose experiences were
outlined in a well-known book entitled The Home of the
Blizzard (Mawson 1915) In an ironic twist of events
the party came ashore at Cape Denison (678S 14278E)
because there was open water right to the coast providing
easy access for their ship The meteorological records
from 1912ndash13 revealed the most intense sustained wind
regime on Earth (Madigan 1929) The anemometer was
recalibrated because of doubts about the extreme condi-
tions experienced and it now appears that the revision
was overly conservative The uncorrected records reveal
an annual average wind speed of 22 m s21 with over 60
of all hourly wind speed reports falling in the range of 15ndash
30 m s21 (Parish and Walker 2006) The easy summer ac-
cess to the coast was caused by the intense katabatic winds
blowing the sea ice offshore to create coastal polynyas
(MoralesMaqueda et al 2004) and therefore choosing this
location turned out to be an unfortunate choice in retro-
spect A similar sequence of extreme katabatic wind events
was experienced in 1912 by a satellite party of the Scott
Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)
e A modern renaissance in historical climatology
The advent of sparse-input reanalysis and reanalysis-
forcedmodeling and reconstruction techniques in recent
years has brought new interest in data that were col-
lected in the past but never integrated into modern
large-scale datasets [eg the International Compre-
hensive OceanndashAtmosphere Data Set (ICOADS) the
International Surface Pressure Databank (ISPD)] A
surprisingly large amount of marine-meteorological and
sea ice data collected in the polar regions by the US
Navy Revenue Cutter ServiceCoast Guard and other
federal vessels since the 1880s has never been extracted
from primary sources and compiled This deficit how-
ever is steadily being reduced through collaborative
data recovery projects organized under the Atmospheric
Circulation Reconstructions over the Earth (ACRE) ini-
tiative (Allan et al 2011) and with support from citizen-
scientists participating in Old Weather (httpwww
oldweatherorg) and similar projects (Freeman et al 2016)
Of particular note in this regard are the sea ice ob-
servations collected in the nineteenth and early twenti-
eth century Some of these data were used in a few early
studies (eg Page 1900 Simpson 1890) and from 1900
to 1939 as occasional contributions to the Danish Me-
teorological Institutersquos annual publication State of the
Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash
1939 1946ndash1956) This publication remains a primary
source of sea ice data for the period in modern datasets for
example the Hadley Centrersquos Sea Ice and Sea Surface
Temperature Dataset version 2 (Titchner and Rayner
2014 Walsh and Chapman 2001) and reanalyses that as-
similate ice information [eg the European Centre for
Medium-Range Weather Forecasts (ECMWF) twentieth
century reanalysis (ERA-20C) Poli et al 2016] Reanalyses
CHAPTER 21 WAL SH ET AL 219
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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Cohen J and Coauthors 2014 Recent Arctic amplification and
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Crawford A and M C Serreze 2015 A new look at the Arctic
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and summer Arctic cyclone activity in the CESM Large En-
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JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
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Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
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Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
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ice in the Arctic seas) I Kommission Hos GEC Gad
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Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
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Dorsey H G Jr 1945 Some meteorological aspects of the
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Douglass A P Newman and S Solomon 2014 The Antarctic
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DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
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R Osinski and A Roberts 2016 Winter atmospheric buoy-
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around southeasternGreenland in theRegionalArctic System
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Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
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English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
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Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
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315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
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1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
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of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
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Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
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101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
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Page J 1900 Ice and ice movements in Bering Sea during the
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Palmeacuten E 1951 The role of atmospheric disturbances in the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
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by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
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Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
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Rodionov S N J E Overland and N A Bond 2005 The
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
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Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
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Screen J A and I Simmonds 2010 The central role of diminishing
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
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Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
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Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
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Taylor P C M Cai A Hu J Meehl W Washington and G J
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Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Thomson A 1948 The growth of meteorological knowledge of
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ThorndikeA S andRColony 1981ArcticOceanBuoy Program
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Timmermans M L J Toole and R Krishfield 2018Warming of the
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Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
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mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
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Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
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JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
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Untersteiner N A S Thorndike D A Rothrock and K L
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Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
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CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
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1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
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van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
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THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
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Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
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von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
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for depicting Arctic sea ice variations back to 1850Geogr Rev
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Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
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Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
the Division of Telegrams and Reports for the Benefit of
Commerce and Agriculture) A break in operations oc-
curred in 1886 and all Signal Service work in Alaska was
abandoned the following year (Henry 1898) In 1890 the
meteorological duties of the Signal Service were trans-
ferred to the US Weather Bureau newly organized as a
civilian agencywithin theUSDepartment ofAgriculture
The Weather Bureau began to rebuild the Alaska station
network in the late 1890s with coverage of the coasts of
Alaska beginning to fill in by 1920 marked by the rees-
tablishment of a station at Point Barrow (Weather Bureau
1925) initially occupied by the Signal Service for the first
IPY in 1881 The development of the station network
between 1867 and 1921 is shown in Fig 21-2 Observations
from these stations have become an important part of the
record used to understand long-term climate trendsmdashin-
sights that depend on data lsquolsquosince record-keeping beganrsquorsquo
The first thorough synthesis studies of the meteorol-
ogy and oceanography of the Pacific Arctic to be pro-
duced in the nineteenth century were made by William
Dall of the US Coast Survey These were Coast Pilot of
Alaska Appendix I Meteorology (Dall 1879) and Report
on the Currents and Temperatures of Bering Sea and the
Adjacent Waters published as Appendix 16 of the Annual
Report of the Superintendent of the US Coast and Geo-
detic Survey (Dall 1882) Both are exhaustive examinations
of the data available from earlier times especially from
Russian and British sources dating back to the 1820s and
included new observations collected by the Coast Survey
the Medical Department of the Army and the Signal Ser-
vice Information was also compiled from whaling ship
captains and other sources both published and from origi-
nal logbooks Dall assembled and published in Coast Pilot
of Alaska Appendix I Meteorology a bibliography and list
of charts containing more than 4000 titles
For Coast Pilot of Alaska Meteorology (1879) Dall
produced the first set of synoptic-scale charts of mean
annual and monthly barometric pressure for the Pacific
Arctic region which provided a reasonable character-
ization of the Aleutian low Dall (1882) notes
The most striking feature presented by the curves ofmean annual pressure is a region of depressed barometerextending fromUnimakPass toKadiak [Kodiak] Island overwhich area so far as the material permits of generalizationa mean pressure is exerted of only 2965 inches This areaof depression which I shall term the Kadiak area was first
FIG 21-1 The USCGC (Coast Guard Cutter) Bearmoored to sea ice in 1918 The Bear was initially purchased by the Navy for the Greely
Relief Expedition in 1884 (Schley 1887) and subsequently served with the Revenue Cutter ServiceCoast Guard in Alaska until 1928 then on
Admiral Byrdrsquos expeditions to Antarctica from 1933 to 1940 and finally with the Navy on the Greenland Patrol during World War II It was
decommissioned for the last time in 1944 (The photograph was provided by the Coast Guard Museum Northwest in Seattle Washington)
CHAPTER 21 WAL SH ET AL 213
FIG 21-2 The meteorological station network developed by the US Army Signal Service and the Weather Bureau in Alaska 1867ndash
1921 The IPY stations at Fort Conger on Ellesmere Island and at Fort Chimo (Kuujjuaq Nunavit) are also included The IPY period is
marked by gray lines The collapse of the Signal Service network in 1887 is apparent
214 METEOROLOG ICAL MONOGRAPHS VOLUME 59
indicated by Mr Ferrel (1875) but from incompleteness ofdata in his possession it was located somewhat too far north
Ferrel at the time with the Coast Survey and subse-
quently with the Signal Service outlined the general cir-
culation of the atmosphere based on physical principles
(Abbe 1892) including the Coriolis force well in advance
of work by Teisserenc de Bort (1883) Exner (1913)
Walker (1923) and others Figure 21-3 shows theNorthern
Hemisphere sea level pressure and prevailing winds for
January from his analysis Dallrsquos (1879) regional map for
the same month (Fig 21-4 top panel) shows a more ac-
curate placement of theAleutian low based on station data
that were unavailable to Ferrel and it provides an example
FIG 21-3 Ferrelrsquos map in Meteorological Researches for the Use of the Coast Pilot (Ferrel 1875) lsquolsquoshowing by isobaric lines the mean
pressure of the atmosphere for January in millimeters reduced to the gravity of the parallel of 458 and by arrows the prevailing directions
of the wind for the Northern Hemispherersquorsquo Although the center of action in the Pacific (Aleutian low) is placed too far north as his
colleague Dall noted the resemblance to modern maps is unmistakable (see eg Hurrell et al 2003 their Figs 1 and 2)
CHAPTER 21 WAL SH ET AL 215
of the characteristic westndasheast split of the Aleutian low
Simultaneous international observations supported this
interpretation (egBulletin of InternationalMeteorological
Observations 1875ndash87 from the US Army Signal Office)
It is now understood that in winter the positions of the one
versus two centers of the Aleutian low are more important
with respect to influence on the Bering Sea environment
than its central pressure (eg Rodionov et al 2005)
Dall also documented general outlines of other im-
portant features of the regional climate in the areas of
meteorology oceanography and biology These include
mean annual and monthly air temperature patterns and
prevailing winds ocean currents and sea surface tem-
peratures the summer distribution of sea ice winds and
temperatures over boreal and tundra regions (Fig 21-4
bottom panel) and associated plants and animals The
FIG 21-4 (top) Dallrsquos (1879) regional map of barometric pressure in January showing a split Aleutian low (referred to by Dall as the
Kadiak area in general with the Kamchatka area appearing in the case of split development) Dall recognized that the lack of data from
the western Aleutians left this question ambiguous but today it is seen to be the correct interpretation (eg Rodionov et al 2005)
(bottom) Dallrsquos (1879) map of summer sea surface isotherms and main ocean currents The average extent of sea ice in summer is also
shown and is generally consistent with what is known about ice distribution in the early satellite era and before (eg Danske
Meteorologiske Institut 1900ndash1939 1946ndash1956 US Hydrographic Office 1946)
216 METEOROLOG ICAL MONOGRAPHS VOLUME 59
oceanography of the Bering Sea is dealt with in more
detail in Dallrsquos subsequent work
In his Report on the Currents and Temperatures of Be-
ring Sea and the Adjacent Waters Dall (1882) turned his
attention to questions that are still relevant today What
ocean currents pass between the Pacific Ocean into the
Bering Sea and thence into the Arctic by way of Bering
Strait or from the Arctic to the south What are the
temperatures of these currents and what effect do they
have on the climate including the distribution of sea ice
As he did in his work on meteorology for the Coast Pilot
Dall scoured the literature (and primary sources) from
around the world for data and collected new oceano-
graphic observations as well in his role as assistant-in-
charge of the Coast Survey vessels Yukon and Humbolt
Of particular note is the hydrographic transect of the
Bering Strait completed in 1880 likely the first ever ob-
tained (Fig 21-5) In part the motivation for the transect
was to test the hypothesis that a branch of the warmKuro
Siwo (Kuroshio) passed through Bering Strait creating
a lsquolsquothermometric gatewayrsquorsquo (Bent 1872) that the USS
Jeannette would have followed into the Arctic At the
same time the USRC (Revenue Cutter) Corwin was
searching the area around Wrangel Island for signs of the
missing ship last seen the previous September in the ice
near Herald Island (Hooper 1881) Unbeknownst to both
Dall and Captain Hooper of the Corwin Commander De
Long and the officers of the Jeannette had already ex-
ploded two of the prevailing myths that inspired their
expedition there was no such thing as a thermometric
gateway andWrangel Land was an island and not a large
landmass extending across the Arctic (De Long 1884)
Dallrsquos hydrographic transect combined with the gen-
eral survey of the region yielded a number of particular
insights He found that the current through the Bering
Strait is mainly to the north although reversible by the
wind and that the northward flow is around 1 ft s21mdash
corresponding to a total flow of 42289425 ft3 s21 (12 Sv
1 Sv [ 106 m3 s21) which corresponds well to modern
measurements (eg Woodgate et al 2005) The tempera-
ture structure resolved by theYukon transect in September
shows the warm Alaska Coastal Current (ACC) on the
FIG 21-5 (top)Map of the Bering Strait region showing surface isotherms and sea ice observed by the US Coast Survey schoonerYukon
in AugustSeptember 1880 and (bottom) the hydrographic section obtained on 5 September 1880 (Dall 1882)
CHAPTER 21 WAL SH ET AL 217
eastern side of the strait and the cold Siberian Coastal
Current (Weingartner et al 1999) on the western side The
presence of sea ice at East Cape and southward seems
unusual when compared with recent data but this was
once a common occurrence (eg Danske Meteorologiske
Institut 1900ndash1939 1946ndash1956)Otherwise the temperature
range found by Dall is fairly typical As to the source of
ocean heat present in the region Dall observed that it was
primarily due to local solar radiation rather than to heat
transported into the area from the Pacific Ocean as sug-
gested by Bent (1872) a result consistent with the recent
findings by Timmermans et al (2018)
b The first International Polar Year
The first IPY is notable as the first attempt to extend
a wide meteorological network into the Arctic and
to collect simultaneous observations with similar well-
calibrated instruments and methods The first IPY was
inspired by the Austro-Hungarian naval officer and sci-
entist Karl Weyprecht (Wood and Overland 2006) The
idea for a coordinated international expedition arose from
his experience as co-commander of the Austro-Hungarian
Polar Expedition of 1872ndash74 After returning home he
reflected on the value of the thousands of meteorological
measurements made during the expedition and noted
But whatever interest all these observations may possessthey do not possess that scientific value even supported bya long column of figures which under other circumstancesmight have been the case They only furnish us with apicture of the extreme effects of the forces of Nature in theArctic regions but they leave us completely in the darkwith respect to their causes (Weyprecht 1875)
To answer that question he understood that large-scale
synchronous data collection was required just as it is now
Weyprechtrsquos address to a meeting of German naturalists
and physicians in 1875 included an enduring assessment
lsquolsquoThe entire meteorology of our day rests upon compari-
son All the successes of which it can boastmdashthe laws of
storms the theories of windsmdashare the result of synchro-
nous observationsrsquorsquo (Wood and Overland 2006)
The Second International Meteorological Congress
held inRome in 1879 supportedWeyprechtrsquos conception
of a coordinated international polar research effort and
established a commission to put it into effect It was to be
as Abbe (1893) described it lsquolsquoa simultaneous invasion of
the polar regions from all sidesrsquorsquo International partici-
pation was invited and in due course 11 nations estab-
lished 14 polar research stations 12 in the Arctic and two
in the subantarctic A number of auxiliary stations were
also established including several in Alaska Participa-
tion by the United States was the responsibility of the
Army Signal Service which established two stations one
at Lady Franklin Bay Ellesmere Island and another at
Point Barrow Alaska Lieutenant Adolphus W Greely
(an early member of the American Meteorological So-
ciety) took command of the former expedition and
Lieutenant Patrick Henry Ray commanded the latter
The results of the first IPY were mixed Lieutenant
Greelyrsquos expedition to Lady Franklin Bay was marred
by the loss of all but seven members to deprivation and
other causes Abbe (1893) stated that
the large volumes and results of the two Signal Service in-ternational polar stations as well as the work of the Polarisand Florence expeditions have contributed not a little toadvance our knowledge of the immense country lying to thenorth of the United States in fact the great importance ofthis work becomes more and more evident as other gov-ernments publish their own contributions to this year ofcooperative research and thus enable us to take a compre-hensive survey of the atmospheric conditions at that time
The full publication of the synchronous observations
unfortunately took 25 yearsmdashit was not completed until
1910 and the data were never analyzed all together as
Weyprecht had envisioned
The meteorological observations of the first IPY were
recently transcribed digitized and assimilated by modern
retrospective analysis (reanalysis) systems (eg Compo
et al 2011) and in this sense have finally fulfilled their in-
tended purpose (Wood and Overland 2006) The greater
legacy of the first IPY may be that its successful demon-
stration of international collaboration in polar science
carried on to three subsequent iterations the second IPY
of 1932ndash33 the International Geophysical Year (or third
IPY) of 1957ndash58 (IGY) and the recent IPY of 2007ndash09
c Arctic work of the Weather Bureau
The Alaska Section of the Weather Bureau was offi-
cially started in 1898 with the establishment of the Climate
and Crop Service and set up of a first-class weather station
at Sitka under the direction ofHLBall (Ball 1898) From
the end of the Signal Service years until the 1920s much of
the meteorological data for the region was collected by
volunteer observers Aside from the Sitka station 10 new
subsidiary stations were also expected to be operated by
volunteers Henry (1898) also noted lsquolsquoIt is hoped that
those to whom instruments have been issued from time to
time in previous years will also revive their interests and
report to [Ball]rsquorsquo Of 18 volunteer stations listed by Henry
that were issued instruments by the Weather Bureau the
most successful were located at Coal Harbor (1889ndash1911)
and Killisnoo (1881ndash1910) Other efforts were not as suc-
cessful Instruments sent to observers in the Northwest
Territories (Canada) were seized and in another case the
observer a missionary was murdered and the records
218 METEOROLOG ICAL MONOGRAPHS VOLUME 59
were lost Further development by theWeather Bureau in
Alaska in the early twentieth century was spurred by
economic development around the gold rush and the es-
tablishment of radio and cable communications (Jessup
2007) as well as the increased need for aviation weather
services beginning in the 1920s (see Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
The Weather Bureaursquos further contributions to polar
meteorology followed a similar pattern as in previous
years although on very small scale Between 1893 and
1902 Evelyn Briggs Baldwin aWeather Bureau observer
took part in three privately supported Arctic adventures
Pearyrsquos North Greenland Expedition in 1893ndash94 the
SecondWellmanExpedition to Franz Josef Land in 1898ndash
99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02
Thiswould be the only polar activity directly related to the
Weather Bureau until the 1920s (Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
d Early Antarctic observations
While efforts by the United States were focused on
the Arctic important work in the Antarctic was being
carried out especially by other nations Major meteo-
rological studies in Antarctica commenced with two
historical expeditions The first was in conjunction with
Robert F Scottrsquos attempt (1910ndash13) to be the first to
reach the South (geographic) Pole Scottrsquos Party peri-
shed in 1912 on the Ross Ice Shelf after having arrived at
the Pole 1 month after Roald Amundsen The role
played by weather in this tragedy remains controversial
to this day (Solomon 2001 Fogt et al 2017) Detailed
meteorological observations were collected during
1911ndash12 at the base location of Cape Evans on Ross
Island by George C Simpson who later became Di-
rector General of theUnited KingdomrsquosMeteorological
Office The reporting and analysis of the observations
were delayed byWorldWar I but appeared in a series of
volumes published in India (Simpson 1919 1921 1923)
Important was that the analysis suggested the origin of
lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)
which became a prime motivation for the establishment
of Byrd Station (808S 1208W) during the IGY (1957)
Although the observations have not been continuous
the early observations from the Byrd Station location
have enabled recent studies to demonstrate large annual
temperature increases since the IGY 228 6 138C from
1958 to 2010 (Bromwich et al 2013 2014)
The second expedition of major meteorological im-
portance was led by Douglas Mawson (the Australasian
Antarctic Expedition 1911ndash14) whose experiences were
outlined in a well-known book entitled The Home of the
Blizzard (Mawson 1915) In an ironic twist of events
the party came ashore at Cape Denison (678S 14278E)
because there was open water right to the coast providing
easy access for their ship The meteorological records
from 1912ndash13 revealed the most intense sustained wind
regime on Earth (Madigan 1929) The anemometer was
recalibrated because of doubts about the extreme condi-
tions experienced and it now appears that the revision
was overly conservative The uncorrected records reveal
an annual average wind speed of 22 m s21 with over 60
of all hourly wind speed reports falling in the range of 15ndash
30 m s21 (Parish and Walker 2006) The easy summer ac-
cess to the coast was caused by the intense katabatic winds
blowing the sea ice offshore to create coastal polynyas
(MoralesMaqueda et al 2004) and therefore choosing this
location turned out to be an unfortunate choice in retro-
spect A similar sequence of extreme katabatic wind events
was experienced in 1912 by a satellite party of the Scott
Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)
e A modern renaissance in historical climatology
The advent of sparse-input reanalysis and reanalysis-
forcedmodeling and reconstruction techniques in recent
years has brought new interest in data that were col-
lected in the past but never integrated into modern
large-scale datasets [eg the International Compre-
hensive OceanndashAtmosphere Data Set (ICOADS) the
International Surface Pressure Databank (ISPD)] A
surprisingly large amount of marine-meteorological and
sea ice data collected in the polar regions by the US
Navy Revenue Cutter ServiceCoast Guard and other
federal vessels since the 1880s has never been extracted
from primary sources and compiled This deficit how-
ever is steadily being reduced through collaborative
data recovery projects organized under the Atmospheric
Circulation Reconstructions over the Earth (ACRE) ini-
tiative (Allan et al 2011) and with support from citizen-
scientists participating in Old Weather (httpwww
oldweatherorg) and similar projects (Freeman et al 2016)
Of particular note in this regard are the sea ice ob-
servations collected in the nineteenth and early twenti-
eth century Some of these data were used in a few early
studies (eg Page 1900 Simpson 1890) and from 1900
to 1939 as occasional contributions to the Danish Me-
teorological Institutersquos annual publication State of the
Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash
1939 1946ndash1956) This publication remains a primary
source of sea ice data for the period in modern datasets for
example the Hadley Centrersquos Sea Ice and Sea Surface
Temperature Dataset version 2 (Titchner and Rayner
2014 Walsh and Chapman 2001) and reanalyses that as-
similate ice information [eg the European Centre for
Medium-Range Weather Forecasts (ECMWF) twentieth
century reanalysis (ERA-20C) Poli et al 2016] Reanalyses
CHAPTER 21 WAL SH ET AL 219
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
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doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
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Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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Binder H M Boettcher C M Grams H Joos S Pfahl and
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Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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Hughes 2004 Polar MM5 simulations of the winter climate of the
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httpsdoiorg1010292008JD010300
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Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
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mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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1010881748-9326102025003
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
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temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
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Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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temperature NOAA Arctic Report Card 2017 httpswww
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7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
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budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
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trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
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Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
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103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
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httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
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Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
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mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
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MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
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1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
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1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
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Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
FIG 21-2 The meteorological station network developed by the US Army Signal Service and the Weather Bureau in Alaska 1867ndash
1921 The IPY stations at Fort Conger on Ellesmere Island and at Fort Chimo (Kuujjuaq Nunavit) are also included The IPY period is
marked by gray lines The collapse of the Signal Service network in 1887 is apparent
214 METEOROLOG ICAL MONOGRAPHS VOLUME 59
indicated by Mr Ferrel (1875) but from incompleteness ofdata in his possession it was located somewhat too far north
Ferrel at the time with the Coast Survey and subse-
quently with the Signal Service outlined the general cir-
culation of the atmosphere based on physical principles
(Abbe 1892) including the Coriolis force well in advance
of work by Teisserenc de Bort (1883) Exner (1913)
Walker (1923) and others Figure 21-3 shows theNorthern
Hemisphere sea level pressure and prevailing winds for
January from his analysis Dallrsquos (1879) regional map for
the same month (Fig 21-4 top panel) shows a more ac-
curate placement of theAleutian low based on station data
that were unavailable to Ferrel and it provides an example
FIG 21-3 Ferrelrsquos map in Meteorological Researches for the Use of the Coast Pilot (Ferrel 1875) lsquolsquoshowing by isobaric lines the mean
pressure of the atmosphere for January in millimeters reduced to the gravity of the parallel of 458 and by arrows the prevailing directions
of the wind for the Northern Hemispherersquorsquo Although the center of action in the Pacific (Aleutian low) is placed too far north as his
colleague Dall noted the resemblance to modern maps is unmistakable (see eg Hurrell et al 2003 their Figs 1 and 2)
CHAPTER 21 WAL SH ET AL 215
of the characteristic westndasheast split of the Aleutian low
Simultaneous international observations supported this
interpretation (egBulletin of InternationalMeteorological
Observations 1875ndash87 from the US Army Signal Office)
It is now understood that in winter the positions of the one
versus two centers of the Aleutian low are more important
with respect to influence on the Bering Sea environment
than its central pressure (eg Rodionov et al 2005)
Dall also documented general outlines of other im-
portant features of the regional climate in the areas of
meteorology oceanography and biology These include
mean annual and monthly air temperature patterns and
prevailing winds ocean currents and sea surface tem-
peratures the summer distribution of sea ice winds and
temperatures over boreal and tundra regions (Fig 21-4
bottom panel) and associated plants and animals The
FIG 21-4 (top) Dallrsquos (1879) regional map of barometric pressure in January showing a split Aleutian low (referred to by Dall as the
Kadiak area in general with the Kamchatka area appearing in the case of split development) Dall recognized that the lack of data from
the western Aleutians left this question ambiguous but today it is seen to be the correct interpretation (eg Rodionov et al 2005)
(bottom) Dallrsquos (1879) map of summer sea surface isotherms and main ocean currents The average extent of sea ice in summer is also
shown and is generally consistent with what is known about ice distribution in the early satellite era and before (eg Danske
Meteorologiske Institut 1900ndash1939 1946ndash1956 US Hydrographic Office 1946)
216 METEOROLOG ICAL MONOGRAPHS VOLUME 59
oceanography of the Bering Sea is dealt with in more
detail in Dallrsquos subsequent work
In his Report on the Currents and Temperatures of Be-
ring Sea and the Adjacent Waters Dall (1882) turned his
attention to questions that are still relevant today What
ocean currents pass between the Pacific Ocean into the
Bering Sea and thence into the Arctic by way of Bering
Strait or from the Arctic to the south What are the
temperatures of these currents and what effect do they
have on the climate including the distribution of sea ice
As he did in his work on meteorology for the Coast Pilot
Dall scoured the literature (and primary sources) from
around the world for data and collected new oceano-
graphic observations as well in his role as assistant-in-
charge of the Coast Survey vessels Yukon and Humbolt
Of particular note is the hydrographic transect of the
Bering Strait completed in 1880 likely the first ever ob-
tained (Fig 21-5) In part the motivation for the transect
was to test the hypothesis that a branch of the warmKuro
Siwo (Kuroshio) passed through Bering Strait creating
a lsquolsquothermometric gatewayrsquorsquo (Bent 1872) that the USS
Jeannette would have followed into the Arctic At the
same time the USRC (Revenue Cutter) Corwin was
searching the area around Wrangel Island for signs of the
missing ship last seen the previous September in the ice
near Herald Island (Hooper 1881) Unbeknownst to both
Dall and Captain Hooper of the Corwin Commander De
Long and the officers of the Jeannette had already ex-
ploded two of the prevailing myths that inspired their
expedition there was no such thing as a thermometric
gateway andWrangel Land was an island and not a large
landmass extending across the Arctic (De Long 1884)
Dallrsquos hydrographic transect combined with the gen-
eral survey of the region yielded a number of particular
insights He found that the current through the Bering
Strait is mainly to the north although reversible by the
wind and that the northward flow is around 1 ft s21mdash
corresponding to a total flow of 42289425 ft3 s21 (12 Sv
1 Sv [ 106 m3 s21) which corresponds well to modern
measurements (eg Woodgate et al 2005) The tempera-
ture structure resolved by theYukon transect in September
shows the warm Alaska Coastal Current (ACC) on the
FIG 21-5 (top)Map of the Bering Strait region showing surface isotherms and sea ice observed by the US Coast Survey schoonerYukon
in AugustSeptember 1880 and (bottom) the hydrographic section obtained on 5 September 1880 (Dall 1882)
CHAPTER 21 WAL SH ET AL 217
eastern side of the strait and the cold Siberian Coastal
Current (Weingartner et al 1999) on the western side The
presence of sea ice at East Cape and southward seems
unusual when compared with recent data but this was
once a common occurrence (eg Danske Meteorologiske
Institut 1900ndash1939 1946ndash1956)Otherwise the temperature
range found by Dall is fairly typical As to the source of
ocean heat present in the region Dall observed that it was
primarily due to local solar radiation rather than to heat
transported into the area from the Pacific Ocean as sug-
gested by Bent (1872) a result consistent with the recent
findings by Timmermans et al (2018)
b The first International Polar Year
The first IPY is notable as the first attempt to extend
a wide meteorological network into the Arctic and
to collect simultaneous observations with similar well-
calibrated instruments and methods The first IPY was
inspired by the Austro-Hungarian naval officer and sci-
entist Karl Weyprecht (Wood and Overland 2006) The
idea for a coordinated international expedition arose from
his experience as co-commander of the Austro-Hungarian
Polar Expedition of 1872ndash74 After returning home he
reflected on the value of the thousands of meteorological
measurements made during the expedition and noted
But whatever interest all these observations may possessthey do not possess that scientific value even supported bya long column of figures which under other circumstancesmight have been the case They only furnish us with apicture of the extreme effects of the forces of Nature in theArctic regions but they leave us completely in the darkwith respect to their causes (Weyprecht 1875)
To answer that question he understood that large-scale
synchronous data collection was required just as it is now
Weyprechtrsquos address to a meeting of German naturalists
and physicians in 1875 included an enduring assessment
lsquolsquoThe entire meteorology of our day rests upon compari-
son All the successes of which it can boastmdashthe laws of
storms the theories of windsmdashare the result of synchro-
nous observationsrsquorsquo (Wood and Overland 2006)
The Second International Meteorological Congress
held inRome in 1879 supportedWeyprechtrsquos conception
of a coordinated international polar research effort and
established a commission to put it into effect It was to be
as Abbe (1893) described it lsquolsquoa simultaneous invasion of
the polar regions from all sidesrsquorsquo International partici-
pation was invited and in due course 11 nations estab-
lished 14 polar research stations 12 in the Arctic and two
in the subantarctic A number of auxiliary stations were
also established including several in Alaska Participa-
tion by the United States was the responsibility of the
Army Signal Service which established two stations one
at Lady Franklin Bay Ellesmere Island and another at
Point Barrow Alaska Lieutenant Adolphus W Greely
(an early member of the American Meteorological So-
ciety) took command of the former expedition and
Lieutenant Patrick Henry Ray commanded the latter
The results of the first IPY were mixed Lieutenant
Greelyrsquos expedition to Lady Franklin Bay was marred
by the loss of all but seven members to deprivation and
other causes Abbe (1893) stated that
the large volumes and results of the two Signal Service in-ternational polar stations as well as the work of the Polarisand Florence expeditions have contributed not a little toadvance our knowledge of the immense country lying to thenorth of the United States in fact the great importance ofthis work becomes more and more evident as other gov-ernments publish their own contributions to this year ofcooperative research and thus enable us to take a compre-hensive survey of the atmospheric conditions at that time
The full publication of the synchronous observations
unfortunately took 25 yearsmdashit was not completed until
1910 and the data were never analyzed all together as
Weyprecht had envisioned
The meteorological observations of the first IPY were
recently transcribed digitized and assimilated by modern
retrospective analysis (reanalysis) systems (eg Compo
et al 2011) and in this sense have finally fulfilled their in-
tended purpose (Wood and Overland 2006) The greater
legacy of the first IPY may be that its successful demon-
stration of international collaboration in polar science
carried on to three subsequent iterations the second IPY
of 1932ndash33 the International Geophysical Year (or third
IPY) of 1957ndash58 (IGY) and the recent IPY of 2007ndash09
c Arctic work of the Weather Bureau
The Alaska Section of the Weather Bureau was offi-
cially started in 1898 with the establishment of the Climate
and Crop Service and set up of a first-class weather station
at Sitka under the direction ofHLBall (Ball 1898) From
the end of the Signal Service years until the 1920s much of
the meteorological data for the region was collected by
volunteer observers Aside from the Sitka station 10 new
subsidiary stations were also expected to be operated by
volunteers Henry (1898) also noted lsquolsquoIt is hoped that
those to whom instruments have been issued from time to
time in previous years will also revive their interests and
report to [Ball]rsquorsquo Of 18 volunteer stations listed by Henry
that were issued instruments by the Weather Bureau the
most successful were located at Coal Harbor (1889ndash1911)
and Killisnoo (1881ndash1910) Other efforts were not as suc-
cessful Instruments sent to observers in the Northwest
Territories (Canada) were seized and in another case the
observer a missionary was murdered and the records
218 METEOROLOG ICAL MONOGRAPHS VOLUME 59
were lost Further development by theWeather Bureau in
Alaska in the early twentieth century was spurred by
economic development around the gold rush and the es-
tablishment of radio and cable communications (Jessup
2007) as well as the increased need for aviation weather
services beginning in the 1920s (see Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
The Weather Bureaursquos further contributions to polar
meteorology followed a similar pattern as in previous
years although on very small scale Between 1893 and
1902 Evelyn Briggs Baldwin aWeather Bureau observer
took part in three privately supported Arctic adventures
Pearyrsquos North Greenland Expedition in 1893ndash94 the
SecondWellmanExpedition to Franz Josef Land in 1898ndash
99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02
Thiswould be the only polar activity directly related to the
Weather Bureau until the 1920s (Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
d Early Antarctic observations
While efforts by the United States were focused on
the Arctic important work in the Antarctic was being
carried out especially by other nations Major meteo-
rological studies in Antarctica commenced with two
historical expeditions The first was in conjunction with
Robert F Scottrsquos attempt (1910ndash13) to be the first to
reach the South (geographic) Pole Scottrsquos Party peri-
shed in 1912 on the Ross Ice Shelf after having arrived at
the Pole 1 month after Roald Amundsen The role
played by weather in this tragedy remains controversial
to this day (Solomon 2001 Fogt et al 2017) Detailed
meteorological observations were collected during
1911ndash12 at the base location of Cape Evans on Ross
Island by George C Simpson who later became Di-
rector General of theUnited KingdomrsquosMeteorological
Office The reporting and analysis of the observations
were delayed byWorldWar I but appeared in a series of
volumes published in India (Simpson 1919 1921 1923)
Important was that the analysis suggested the origin of
lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)
which became a prime motivation for the establishment
of Byrd Station (808S 1208W) during the IGY (1957)
Although the observations have not been continuous
the early observations from the Byrd Station location
have enabled recent studies to demonstrate large annual
temperature increases since the IGY 228 6 138C from
1958 to 2010 (Bromwich et al 2013 2014)
The second expedition of major meteorological im-
portance was led by Douglas Mawson (the Australasian
Antarctic Expedition 1911ndash14) whose experiences were
outlined in a well-known book entitled The Home of the
Blizzard (Mawson 1915) In an ironic twist of events
the party came ashore at Cape Denison (678S 14278E)
because there was open water right to the coast providing
easy access for their ship The meteorological records
from 1912ndash13 revealed the most intense sustained wind
regime on Earth (Madigan 1929) The anemometer was
recalibrated because of doubts about the extreme condi-
tions experienced and it now appears that the revision
was overly conservative The uncorrected records reveal
an annual average wind speed of 22 m s21 with over 60
of all hourly wind speed reports falling in the range of 15ndash
30 m s21 (Parish and Walker 2006) The easy summer ac-
cess to the coast was caused by the intense katabatic winds
blowing the sea ice offshore to create coastal polynyas
(MoralesMaqueda et al 2004) and therefore choosing this
location turned out to be an unfortunate choice in retro-
spect A similar sequence of extreme katabatic wind events
was experienced in 1912 by a satellite party of the Scott
Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)
e A modern renaissance in historical climatology
The advent of sparse-input reanalysis and reanalysis-
forcedmodeling and reconstruction techniques in recent
years has brought new interest in data that were col-
lected in the past but never integrated into modern
large-scale datasets [eg the International Compre-
hensive OceanndashAtmosphere Data Set (ICOADS) the
International Surface Pressure Databank (ISPD)] A
surprisingly large amount of marine-meteorological and
sea ice data collected in the polar regions by the US
Navy Revenue Cutter ServiceCoast Guard and other
federal vessels since the 1880s has never been extracted
from primary sources and compiled This deficit how-
ever is steadily being reduced through collaborative
data recovery projects organized under the Atmospheric
Circulation Reconstructions over the Earth (ACRE) ini-
tiative (Allan et al 2011) and with support from citizen-
scientists participating in Old Weather (httpwww
oldweatherorg) and similar projects (Freeman et al 2016)
Of particular note in this regard are the sea ice ob-
servations collected in the nineteenth and early twenti-
eth century Some of these data were used in a few early
studies (eg Page 1900 Simpson 1890) and from 1900
to 1939 as occasional contributions to the Danish Me-
teorological Institutersquos annual publication State of the
Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash
1939 1946ndash1956) This publication remains a primary
source of sea ice data for the period in modern datasets for
example the Hadley Centrersquos Sea Ice and Sea Surface
Temperature Dataset version 2 (Titchner and Rayner
2014 Walsh and Chapman 2001) and reanalyses that as-
similate ice information [eg the European Centre for
Medium-Range Weather Forecasts (ECMWF) twentieth
century reanalysis (ERA-20C) Poli et al 2016] Reanalyses
CHAPTER 21 WAL SH ET AL 219
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
REFERENCES
Abbe C 1892 Memoir of William Ferrel 1817ndash1891 Biograph-
ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
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tion Reconstructions over the Earth (ACRE) Initiative Bull
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
ternational Polar Years (IPYs) From Pole to Pole Vol 1
Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
covery 1776ndash1880 Part 1 Journals of Captain James Cook on his
Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
Bedel B 1954 Les observations meacuteteacuteorologiques de la station
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tude (Meteorological observations of the French Greenland
station atmospheric conditions at altitude) Expeacuteditions Po-laires Franccedilaises Missions Paul-Emile Victor Resultats Sci-
entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
early twentieth-century warming in the ArcticmdashA possible
mechanism J Climate 17 4045ndash4057 httpsdoiorg1011751520-0442(2004)0174045TETWIT20CO2
Bent S 1872 Thermal Paths to the Pole An Address Delivered
before the St Louis Mercantile Library Association RP
Studley Co 40 pp
Bessels E 1876 Scientific results of the United States Arctic ex-
pedition Steamer Polaris CF Hall commanding US Navy
Rep Government Printing Office 986 pp httpsarchive
orgdetailscu31924029881095pagen5
Binder H M Boettcher C M Grams H Joos S Pfahl and
H Wernli 2017 Exceptional air mass transport and dy-
namical drivers of an extreme wintertime Arctic warm
eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg
1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
bridge University Press 867ndash952
Bockstoce J R and D B Botkin 1983 The historical status and re-
duction of thewesternArctic bowheadwhale (Balaenamysticetus)
population by the pelagic whaling industry 1848ndash1914 In-
ternational Whaling Commission Rep SC32PS16 107ndash141 pp
httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
katabatic winds and the Terra Nova Bay polynya Polar Rec
21 137ndash146 httpsdoiorg101017S0032247400004514
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and NCEPNCAR reanalyses in the high and middle latitudes
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mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner
1993 Spatial and temporal variations of the intense katabatic
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and Climatology Studies Based on Automatic Weather Sta-
tions D H Bromwich and C R Stearns Eds Antarctic
Research Series Vol 61 Amer Geophys Union 47ndash68
mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
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doiorg1011751520-0442(2004)0173415PMSOTW20CO2
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Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
httpsdoiorg1010292008JD010300
mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
since 1989 in contemporary global reanalyses J Climate 24
4189ndash4209 httpsdoiorg1011752011JCLI40741
mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
arctica among the most rapidly warming regions on Earth
Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash and mdashmdash 2014 Corrigendum
Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
changing climate Environ Res Lett 10 025003 httpsdoiorg
1010881748-9326102025003
2130 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
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doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
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1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
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ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
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mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
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(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
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orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
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Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
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7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
indicated by Mr Ferrel (1875) but from incompleteness ofdata in his possession it was located somewhat too far north
Ferrel at the time with the Coast Survey and subse-
quently with the Signal Service outlined the general cir-
culation of the atmosphere based on physical principles
(Abbe 1892) including the Coriolis force well in advance
of work by Teisserenc de Bort (1883) Exner (1913)
Walker (1923) and others Figure 21-3 shows theNorthern
Hemisphere sea level pressure and prevailing winds for
January from his analysis Dallrsquos (1879) regional map for
the same month (Fig 21-4 top panel) shows a more ac-
curate placement of theAleutian low based on station data
that were unavailable to Ferrel and it provides an example
FIG 21-3 Ferrelrsquos map in Meteorological Researches for the Use of the Coast Pilot (Ferrel 1875) lsquolsquoshowing by isobaric lines the mean
pressure of the atmosphere for January in millimeters reduced to the gravity of the parallel of 458 and by arrows the prevailing directions
of the wind for the Northern Hemispherersquorsquo Although the center of action in the Pacific (Aleutian low) is placed too far north as his
colleague Dall noted the resemblance to modern maps is unmistakable (see eg Hurrell et al 2003 their Figs 1 and 2)
CHAPTER 21 WAL SH ET AL 215
of the characteristic westndasheast split of the Aleutian low
Simultaneous international observations supported this
interpretation (egBulletin of InternationalMeteorological
Observations 1875ndash87 from the US Army Signal Office)
It is now understood that in winter the positions of the one
versus two centers of the Aleutian low are more important
with respect to influence on the Bering Sea environment
than its central pressure (eg Rodionov et al 2005)
Dall also documented general outlines of other im-
portant features of the regional climate in the areas of
meteorology oceanography and biology These include
mean annual and monthly air temperature patterns and
prevailing winds ocean currents and sea surface tem-
peratures the summer distribution of sea ice winds and
temperatures over boreal and tundra regions (Fig 21-4
bottom panel) and associated plants and animals The
FIG 21-4 (top) Dallrsquos (1879) regional map of barometric pressure in January showing a split Aleutian low (referred to by Dall as the
Kadiak area in general with the Kamchatka area appearing in the case of split development) Dall recognized that the lack of data from
the western Aleutians left this question ambiguous but today it is seen to be the correct interpretation (eg Rodionov et al 2005)
(bottom) Dallrsquos (1879) map of summer sea surface isotherms and main ocean currents The average extent of sea ice in summer is also
shown and is generally consistent with what is known about ice distribution in the early satellite era and before (eg Danske
Meteorologiske Institut 1900ndash1939 1946ndash1956 US Hydrographic Office 1946)
216 METEOROLOG ICAL MONOGRAPHS VOLUME 59
oceanography of the Bering Sea is dealt with in more
detail in Dallrsquos subsequent work
In his Report on the Currents and Temperatures of Be-
ring Sea and the Adjacent Waters Dall (1882) turned his
attention to questions that are still relevant today What
ocean currents pass between the Pacific Ocean into the
Bering Sea and thence into the Arctic by way of Bering
Strait or from the Arctic to the south What are the
temperatures of these currents and what effect do they
have on the climate including the distribution of sea ice
As he did in his work on meteorology for the Coast Pilot
Dall scoured the literature (and primary sources) from
around the world for data and collected new oceano-
graphic observations as well in his role as assistant-in-
charge of the Coast Survey vessels Yukon and Humbolt
Of particular note is the hydrographic transect of the
Bering Strait completed in 1880 likely the first ever ob-
tained (Fig 21-5) In part the motivation for the transect
was to test the hypothesis that a branch of the warmKuro
Siwo (Kuroshio) passed through Bering Strait creating
a lsquolsquothermometric gatewayrsquorsquo (Bent 1872) that the USS
Jeannette would have followed into the Arctic At the
same time the USRC (Revenue Cutter) Corwin was
searching the area around Wrangel Island for signs of the
missing ship last seen the previous September in the ice
near Herald Island (Hooper 1881) Unbeknownst to both
Dall and Captain Hooper of the Corwin Commander De
Long and the officers of the Jeannette had already ex-
ploded two of the prevailing myths that inspired their
expedition there was no such thing as a thermometric
gateway andWrangel Land was an island and not a large
landmass extending across the Arctic (De Long 1884)
Dallrsquos hydrographic transect combined with the gen-
eral survey of the region yielded a number of particular
insights He found that the current through the Bering
Strait is mainly to the north although reversible by the
wind and that the northward flow is around 1 ft s21mdash
corresponding to a total flow of 42289425 ft3 s21 (12 Sv
1 Sv [ 106 m3 s21) which corresponds well to modern
measurements (eg Woodgate et al 2005) The tempera-
ture structure resolved by theYukon transect in September
shows the warm Alaska Coastal Current (ACC) on the
FIG 21-5 (top)Map of the Bering Strait region showing surface isotherms and sea ice observed by the US Coast Survey schoonerYukon
in AugustSeptember 1880 and (bottom) the hydrographic section obtained on 5 September 1880 (Dall 1882)
CHAPTER 21 WAL SH ET AL 217
eastern side of the strait and the cold Siberian Coastal
Current (Weingartner et al 1999) on the western side The
presence of sea ice at East Cape and southward seems
unusual when compared with recent data but this was
once a common occurrence (eg Danske Meteorologiske
Institut 1900ndash1939 1946ndash1956)Otherwise the temperature
range found by Dall is fairly typical As to the source of
ocean heat present in the region Dall observed that it was
primarily due to local solar radiation rather than to heat
transported into the area from the Pacific Ocean as sug-
gested by Bent (1872) a result consistent with the recent
findings by Timmermans et al (2018)
b The first International Polar Year
The first IPY is notable as the first attempt to extend
a wide meteorological network into the Arctic and
to collect simultaneous observations with similar well-
calibrated instruments and methods The first IPY was
inspired by the Austro-Hungarian naval officer and sci-
entist Karl Weyprecht (Wood and Overland 2006) The
idea for a coordinated international expedition arose from
his experience as co-commander of the Austro-Hungarian
Polar Expedition of 1872ndash74 After returning home he
reflected on the value of the thousands of meteorological
measurements made during the expedition and noted
But whatever interest all these observations may possessthey do not possess that scientific value even supported bya long column of figures which under other circumstancesmight have been the case They only furnish us with apicture of the extreme effects of the forces of Nature in theArctic regions but they leave us completely in the darkwith respect to their causes (Weyprecht 1875)
To answer that question he understood that large-scale
synchronous data collection was required just as it is now
Weyprechtrsquos address to a meeting of German naturalists
and physicians in 1875 included an enduring assessment
lsquolsquoThe entire meteorology of our day rests upon compari-
son All the successes of which it can boastmdashthe laws of
storms the theories of windsmdashare the result of synchro-
nous observationsrsquorsquo (Wood and Overland 2006)
The Second International Meteorological Congress
held inRome in 1879 supportedWeyprechtrsquos conception
of a coordinated international polar research effort and
established a commission to put it into effect It was to be
as Abbe (1893) described it lsquolsquoa simultaneous invasion of
the polar regions from all sidesrsquorsquo International partici-
pation was invited and in due course 11 nations estab-
lished 14 polar research stations 12 in the Arctic and two
in the subantarctic A number of auxiliary stations were
also established including several in Alaska Participa-
tion by the United States was the responsibility of the
Army Signal Service which established two stations one
at Lady Franklin Bay Ellesmere Island and another at
Point Barrow Alaska Lieutenant Adolphus W Greely
(an early member of the American Meteorological So-
ciety) took command of the former expedition and
Lieutenant Patrick Henry Ray commanded the latter
The results of the first IPY were mixed Lieutenant
Greelyrsquos expedition to Lady Franklin Bay was marred
by the loss of all but seven members to deprivation and
other causes Abbe (1893) stated that
the large volumes and results of the two Signal Service in-ternational polar stations as well as the work of the Polarisand Florence expeditions have contributed not a little toadvance our knowledge of the immense country lying to thenorth of the United States in fact the great importance ofthis work becomes more and more evident as other gov-ernments publish their own contributions to this year ofcooperative research and thus enable us to take a compre-hensive survey of the atmospheric conditions at that time
The full publication of the synchronous observations
unfortunately took 25 yearsmdashit was not completed until
1910 and the data were never analyzed all together as
Weyprecht had envisioned
The meteorological observations of the first IPY were
recently transcribed digitized and assimilated by modern
retrospective analysis (reanalysis) systems (eg Compo
et al 2011) and in this sense have finally fulfilled their in-
tended purpose (Wood and Overland 2006) The greater
legacy of the first IPY may be that its successful demon-
stration of international collaboration in polar science
carried on to three subsequent iterations the second IPY
of 1932ndash33 the International Geophysical Year (or third
IPY) of 1957ndash58 (IGY) and the recent IPY of 2007ndash09
c Arctic work of the Weather Bureau
The Alaska Section of the Weather Bureau was offi-
cially started in 1898 with the establishment of the Climate
and Crop Service and set up of a first-class weather station
at Sitka under the direction ofHLBall (Ball 1898) From
the end of the Signal Service years until the 1920s much of
the meteorological data for the region was collected by
volunteer observers Aside from the Sitka station 10 new
subsidiary stations were also expected to be operated by
volunteers Henry (1898) also noted lsquolsquoIt is hoped that
those to whom instruments have been issued from time to
time in previous years will also revive their interests and
report to [Ball]rsquorsquo Of 18 volunteer stations listed by Henry
that were issued instruments by the Weather Bureau the
most successful were located at Coal Harbor (1889ndash1911)
and Killisnoo (1881ndash1910) Other efforts were not as suc-
cessful Instruments sent to observers in the Northwest
Territories (Canada) were seized and in another case the
observer a missionary was murdered and the records
218 METEOROLOG ICAL MONOGRAPHS VOLUME 59
were lost Further development by theWeather Bureau in
Alaska in the early twentieth century was spurred by
economic development around the gold rush and the es-
tablishment of radio and cable communications (Jessup
2007) as well as the increased need for aviation weather
services beginning in the 1920s (see Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
The Weather Bureaursquos further contributions to polar
meteorology followed a similar pattern as in previous
years although on very small scale Between 1893 and
1902 Evelyn Briggs Baldwin aWeather Bureau observer
took part in three privately supported Arctic adventures
Pearyrsquos North Greenland Expedition in 1893ndash94 the
SecondWellmanExpedition to Franz Josef Land in 1898ndash
99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02
Thiswould be the only polar activity directly related to the
Weather Bureau until the 1920s (Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
d Early Antarctic observations
While efforts by the United States were focused on
the Arctic important work in the Antarctic was being
carried out especially by other nations Major meteo-
rological studies in Antarctica commenced with two
historical expeditions The first was in conjunction with
Robert F Scottrsquos attempt (1910ndash13) to be the first to
reach the South (geographic) Pole Scottrsquos Party peri-
shed in 1912 on the Ross Ice Shelf after having arrived at
the Pole 1 month after Roald Amundsen The role
played by weather in this tragedy remains controversial
to this day (Solomon 2001 Fogt et al 2017) Detailed
meteorological observations were collected during
1911ndash12 at the base location of Cape Evans on Ross
Island by George C Simpson who later became Di-
rector General of theUnited KingdomrsquosMeteorological
Office The reporting and analysis of the observations
were delayed byWorldWar I but appeared in a series of
volumes published in India (Simpson 1919 1921 1923)
Important was that the analysis suggested the origin of
lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)
which became a prime motivation for the establishment
of Byrd Station (808S 1208W) during the IGY (1957)
Although the observations have not been continuous
the early observations from the Byrd Station location
have enabled recent studies to demonstrate large annual
temperature increases since the IGY 228 6 138C from
1958 to 2010 (Bromwich et al 2013 2014)
The second expedition of major meteorological im-
portance was led by Douglas Mawson (the Australasian
Antarctic Expedition 1911ndash14) whose experiences were
outlined in a well-known book entitled The Home of the
Blizzard (Mawson 1915) In an ironic twist of events
the party came ashore at Cape Denison (678S 14278E)
because there was open water right to the coast providing
easy access for their ship The meteorological records
from 1912ndash13 revealed the most intense sustained wind
regime on Earth (Madigan 1929) The anemometer was
recalibrated because of doubts about the extreme condi-
tions experienced and it now appears that the revision
was overly conservative The uncorrected records reveal
an annual average wind speed of 22 m s21 with over 60
of all hourly wind speed reports falling in the range of 15ndash
30 m s21 (Parish and Walker 2006) The easy summer ac-
cess to the coast was caused by the intense katabatic winds
blowing the sea ice offshore to create coastal polynyas
(MoralesMaqueda et al 2004) and therefore choosing this
location turned out to be an unfortunate choice in retro-
spect A similar sequence of extreme katabatic wind events
was experienced in 1912 by a satellite party of the Scott
Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)
e A modern renaissance in historical climatology
The advent of sparse-input reanalysis and reanalysis-
forcedmodeling and reconstruction techniques in recent
years has brought new interest in data that were col-
lected in the past but never integrated into modern
large-scale datasets [eg the International Compre-
hensive OceanndashAtmosphere Data Set (ICOADS) the
International Surface Pressure Databank (ISPD)] A
surprisingly large amount of marine-meteorological and
sea ice data collected in the polar regions by the US
Navy Revenue Cutter ServiceCoast Guard and other
federal vessels since the 1880s has never been extracted
from primary sources and compiled This deficit how-
ever is steadily being reduced through collaborative
data recovery projects organized under the Atmospheric
Circulation Reconstructions over the Earth (ACRE) ini-
tiative (Allan et al 2011) and with support from citizen-
scientists participating in Old Weather (httpwww
oldweatherorg) and similar projects (Freeman et al 2016)
Of particular note in this regard are the sea ice ob-
servations collected in the nineteenth and early twenti-
eth century Some of these data were used in a few early
studies (eg Page 1900 Simpson 1890) and from 1900
to 1939 as occasional contributions to the Danish Me-
teorological Institutersquos annual publication State of the
Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash
1939 1946ndash1956) This publication remains a primary
source of sea ice data for the period in modern datasets for
example the Hadley Centrersquos Sea Ice and Sea Surface
Temperature Dataset version 2 (Titchner and Rayner
2014 Walsh and Chapman 2001) and reanalyses that as-
similate ice information [eg the European Centre for
Medium-Range Weather Forecasts (ECMWF) twentieth
century reanalysis (ERA-20C) Poli et al 2016] Reanalyses
CHAPTER 21 WAL SH ET AL 219
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Allan R P Brohan G Compo R Stone J Luterbacher and
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Barnes E A and J A Screen 2015 The impact of Arctic
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Barr S and C Luumldecke Eds 2010 The History of the In-
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Barry R G 1967 Seasonal location of theArctic front over North
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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The Physical Science Basis T F Stocker et al Eds Cam-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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and NCEPNCAR reanalyses in the high and middle latitudes
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1993 Spatial and temporal variations of the intense katabatic
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mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
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j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
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Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
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Candlish L M R L Raddatz G G Gunn M G Asplin and
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over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
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Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
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Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
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Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
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1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
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1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
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Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Summer snowfall impact on the Greenland Ice Sheet Cryo-
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
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mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
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mdashmdash and R Walker 2006 A re-examination of the winds of
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
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2002 Measurements near the atmospheric surface group
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
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Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
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trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
of the characteristic westndasheast split of the Aleutian low
Simultaneous international observations supported this
interpretation (egBulletin of InternationalMeteorological
Observations 1875ndash87 from the US Army Signal Office)
It is now understood that in winter the positions of the one
versus two centers of the Aleutian low are more important
with respect to influence on the Bering Sea environment
than its central pressure (eg Rodionov et al 2005)
Dall also documented general outlines of other im-
portant features of the regional climate in the areas of
meteorology oceanography and biology These include
mean annual and monthly air temperature patterns and
prevailing winds ocean currents and sea surface tem-
peratures the summer distribution of sea ice winds and
temperatures over boreal and tundra regions (Fig 21-4
bottom panel) and associated plants and animals The
FIG 21-4 (top) Dallrsquos (1879) regional map of barometric pressure in January showing a split Aleutian low (referred to by Dall as the
Kadiak area in general with the Kamchatka area appearing in the case of split development) Dall recognized that the lack of data from
the western Aleutians left this question ambiguous but today it is seen to be the correct interpretation (eg Rodionov et al 2005)
(bottom) Dallrsquos (1879) map of summer sea surface isotherms and main ocean currents The average extent of sea ice in summer is also
shown and is generally consistent with what is known about ice distribution in the early satellite era and before (eg Danske
Meteorologiske Institut 1900ndash1939 1946ndash1956 US Hydrographic Office 1946)
216 METEOROLOG ICAL MONOGRAPHS VOLUME 59
oceanography of the Bering Sea is dealt with in more
detail in Dallrsquos subsequent work
In his Report on the Currents and Temperatures of Be-
ring Sea and the Adjacent Waters Dall (1882) turned his
attention to questions that are still relevant today What
ocean currents pass between the Pacific Ocean into the
Bering Sea and thence into the Arctic by way of Bering
Strait or from the Arctic to the south What are the
temperatures of these currents and what effect do they
have on the climate including the distribution of sea ice
As he did in his work on meteorology for the Coast Pilot
Dall scoured the literature (and primary sources) from
around the world for data and collected new oceano-
graphic observations as well in his role as assistant-in-
charge of the Coast Survey vessels Yukon and Humbolt
Of particular note is the hydrographic transect of the
Bering Strait completed in 1880 likely the first ever ob-
tained (Fig 21-5) In part the motivation for the transect
was to test the hypothesis that a branch of the warmKuro
Siwo (Kuroshio) passed through Bering Strait creating
a lsquolsquothermometric gatewayrsquorsquo (Bent 1872) that the USS
Jeannette would have followed into the Arctic At the
same time the USRC (Revenue Cutter) Corwin was
searching the area around Wrangel Island for signs of the
missing ship last seen the previous September in the ice
near Herald Island (Hooper 1881) Unbeknownst to both
Dall and Captain Hooper of the Corwin Commander De
Long and the officers of the Jeannette had already ex-
ploded two of the prevailing myths that inspired their
expedition there was no such thing as a thermometric
gateway andWrangel Land was an island and not a large
landmass extending across the Arctic (De Long 1884)
Dallrsquos hydrographic transect combined with the gen-
eral survey of the region yielded a number of particular
insights He found that the current through the Bering
Strait is mainly to the north although reversible by the
wind and that the northward flow is around 1 ft s21mdash
corresponding to a total flow of 42289425 ft3 s21 (12 Sv
1 Sv [ 106 m3 s21) which corresponds well to modern
measurements (eg Woodgate et al 2005) The tempera-
ture structure resolved by theYukon transect in September
shows the warm Alaska Coastal Current (ACC) on the
FIG 21-5 (top)Map of the Bering Strait region showing surface isotherms and sea ice observed by the US Coast Survey schoonerYukon
in AugustSeptember 1880 and (bottom) the hydrographic section obtained on 5 September 1880 (Dall 1882)
CHAPTER 21 WAL SH ET AL 217
eastern side of the strait and the cold Siberian Coastal
Current (Weingartner et al 1999) on the western side The
presence of sea ice at East Cape and southward seems
unusual when compared with recent data but this was
once a common occurrence (eg Danske Meteorologiske
Institut 1900ndash1939 1946ndash1956)Otherwise the temperature
range found by Dall is fairly typical As to the source of
ocean heat present in the region Dall observed that it was
primarily due to local solar radiation rather than to heat
transported into the area from the Pacific Ocean as sug-
gested by Bent (1872) a result consistent with the recent
findings by Timmermans et al (2018)
b The first International Polar Year
The first IPY is notable as the first attempt to extend
a wide meteorological network into the Arctic and
to collect simultaneous observations with similar well-
calibrated instruments and methods The first IPY was
inspired by the Austro-Hungarian naval officer and sci-
entist Karl Weyprecht (Wood and Overland 2006) The
idea for a coordinated international expedition arose from
his experience as co-commander of the Austro-Hungarian
Polar Expedition of 1872ndash74 After returning home he
reflected on the value of the thousands of meteorological
measurements made during the expedition and noted
But whatever interest all these observations may possessthey do not possess that scientific value even supported bya long column of figures which under other circumstancesmight have been the case They only furnish us with apicture of the extreme effects of the forces of Nature in theArctic regions but they leave us completely in the darkwith respect to their causes (Weyprecht 1875)
To answer that question he understood that large-scale
synchronous data collection was required just as it is now
Weyprechtrsquos address to a meeting of German naturalists
and physicians in 1875 included an enduring assessment
lsquolsquoThe entire meteorology of our day rests upon compari-
son All the successes of which it can boastmdashthe laws of
storms the theories of windsmdashare the result of synchro-
nous observationsrsquorsquo (Wood and Overland 2006)
The Second International Meteorological Congress
held inRome in 1879 supportedWeyprechtrsquos conception
of a coordinated international polar research effort and
established a commission to put it into effect It was to be
as Abbe (1893) described it lsquolsquoa simultaneous invasion of
the polar regions from all sidesrsquorsquo International partici-
pation was invited and in due course 11 nations estab-
lished 14 polar research stations 12 in the Arctic and two
in the subantarctic A number of auxiliary stations were
also established including several in Alaska Participa-
tion by the United States was the responsibility of the
Army Signal Service which established two stations one
at Lady Franklin Bay Ellesmere Island and another at
Point Barrow Alaska Lieutenant Adolphus W Greely
(an early member of the American Meteorological So-
ciety) took command of the former expedition and
Lieutenant Patrick Henry Ray commanded the latter
The results of the first IPY were mixed Lieutenant
Greelyrsquos expedition to Lady Franklin Bay was marred
by the loss of all but seven members to deprivation and
other causes Abbe (1893) stated that
the large volumes and results of the two Signal Service in-ternational polar stations as well as the work of the Polarisand Florence expeditions have contributed not a little toadvance our knowledge of the immense country lying to thenorth of the United States in fact the great importance ofthis work becomes more and more evident as other gov-ernments publish their own contributions to this year ofcooperative research and thus enable us to take a compre-hensive survey of the atmospheric conditions at that time
The full publication of the synchronous observations
unfortunately took 25 yearsmdashit was not completed until
1910 and the data were never analyzed all together as
Weyprecht had envisioned
The meteorological observations of the first IPY were
recently transcribed digitized and assimilated by modern
retrospective analysis (reanalysis) systems (eg Compo
et al 2011) and in this sense have finally fulfilled their in-
tended purpose (Wood and Overland 2006) The greater
legacy of the first IPY may be that its successful demon-
stration of international collaboration in polar science
carried on to three subsequent iterations the second IPY
of 1932ndash33 the International Geophysical Year (or third
IPY) of 1957ndash58 (IGY) and the recent IPY of 2007ndash09
c Arctic work of the Weather Bureau
The Alaska Section of the Weather Bureau was offi-
cially started in 1898 with the establishment of the Climate
and Crop Service and set up of a first-class weather station
at Sitka under the direction ofHLBall (Ball 1898) From
the end of the Signal Service years until the 1920s much of
the meteorological data for the region was collected by
volunteer observers Aside from the Sitka station 10 new
subsidiary stations were also expected to be operated by
volunteers Henry (1898) also noted lsquolsquoIt is hoped that
those to whom instruments have been issued from time to
time in previous years will also revive their interests and
report to [Ball]rsquorsquo Of 18 volunteer stations listed by Henry
that were issued instruments by the Weather Bureau the
most successful were located at Coal Harbor (1889ndash1911)
and Killisnoo (1881ndash1910) Other efforts were not as suc-
cessful Instruments sent to observers in the Northwest
Territories (Canada) were seized and in another case the
observer a missionary was murdered and the records
218 METEOROLOG ICAL MONOGRAPHS VOLUME 59
were lost Further development by theWeather Bureau in
Alaska in the early twentieth century was spurred by
economic development around the gold rush and the es-
tablishment of radio and cable communications (Jessup
2007) as well as the increased need for aviation weather
services beginning in the 1920s (see Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
The Weather Bureaursquos further contributions to polar
meteorology followed a similar pattern as in previous
years although on very small scale Between 1893 and
1902 Evelyn Briggs Baldwin aWeather Bureau observer
took part in three privately supported Arctic adventures
Pearyrsquos North Greenland Expedition in 1893ndash94 the
SecondWellmanExpedition to Franz Josef Land in 1898ndash
99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02
Thiswould be the only polar activity directly related to the
Weather Bureau until the 1920s (Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
d Early Antarctic observations
While efforts by the United States were focused on
the Arctic important work in the Antarctic was being
carried out especially by other nations Major meteo-
rological studies in Antarctica commenced with two
historical expeditions The first was in conjunction with
Robert F Scottrsquos attempt (1910ndash13) to be the first to
reach the South (geographic) Pole Scottrsquos Party peri-
shed in 1912 on the Ross Ice Shelf after having arrived at
the Pole 1 month after Roald Amundsen The role
played by weather in this tragedy remains controversial
to this day (Solomon 2001 Fogt et al 2017) Detailed
meteorological observations were collected during
1911ndash12 at the base location of Cape Evans on Ross
Island by George C Simpson who later became Di-
rector General of theUnited KingdomrsquosMeteorological
Office The reporting and analysis of the observations
were delayed byWorldWar I but appeared in a series of
volumes published in India (Simpson 1919 1921 1923)
Important was that the analysis suggested the origin of
lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)
which became a prime motivation for the establishment
of Byrd Station (808S 1208W) during the IGY (1957)
Although the observations have not been continuous
the early observations from the Byrd Station location
have enabled recent studies to demonstrate large annual
temperature increases since the IGY 228 6 138C from
1958 to 2010 (Bromwich et al 2013 2014)
The second expedition of major meteorological im-
portance was led by Douglas Mawson (the Australasian
Antarctic Expedition 1911ndash14) whose experiences were
outlined in a well-known book entitled The Home of the
Blizzard (Mawson 1915) In an ironic twist of events
the party came ashore at Cape Denison (678S 14278E)
because there was open water right to the coast providing
easy access for their ship The meteorological records
from 1912ndash13 revealed the most intense sustained wind
regime on Earth (Madigan 1929) The anemometer was
recalibrated because of doubts about the extreme condi-
tions experienced and it now appears that the revision
was overly conservative The uncorrected records reveal
an annual average wind speed of 22 m s21 with over 60
of all hourly wind speed reports falling in the range of 15ndash
30 m s21 (Parish and Walker 2006) The easy summer ac-
cess to the coast was caused by the intense katabatic winds
blowing the sea ice offshore to create coastal polynyas
(MoralesMaqueda et al 2004) and therefore choosing this
location turned out to be an unfortunate choice in retro-
spect A similar sequence of extreme katabatic wind events
was experienced in 1912 by a satellite party of the Scott
Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)
e A modern renaissance in historical climatology
The advent of sparse-input reanalysis and reanalysis-
forcedmodeling and reconstruction techniques in recent
years has brought new interest in data that were col-
lected in the past but never integrated into modern
large-scale datasets [eg the International Compre-
hensive OceanndashAtmosphere Data Set (ICOADS) the
International Surface Pressure Databank (ISPD)] A
surprisingly large amount of marine-meteorological and
sea ice data collected in the polar regions by the US
Navy Revenue Cutter ServiceCoast Guard and other
federal vessels since the 1880s has never been extracted
from primary sources and compiled This deficit how-
ever is steadily being reduced through collaborative
data recovery projects organized under the Atmospheric
Circulation Reconstructions over the Earth (ACRE) ini-
tiative (Allan et al 2011) and with support from citizen-
scientists participating in Old Weather (httpwww
oldweatherorg) and similar projects (Freeman et al 2016)
Of particular note in this regard are the sea ice ob-
servations collected in the nineteenth and early twenti-
eth century Some of these data were used in a few early
studies (eg Page 1900 Simpson 1890) and from 1900
to 1939 as occasional contributions to the Danish Me-
teorological Institutersquos annual publication State of the
Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash
1939 1946ndash1956) This publication remains a primary
source of sea ice data for the period in modern datasets for
example the Hadley Centrersquos Sea Ice and Sea Surface
Temperature Dataset version 2 (Titchner and Rayner
2014 Walsh and Chapman 2001) and reanalyses that as-
similate ice information [eg the European Centre for
Medium-Range Weather Forecasts (ECMWF) twentieth
century reanalysis (ERA-20C) Poli et al 2016] Reanalyses
CHAPTER 21 WAL SH ET AL 219
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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Cohen J and Coauthors 2014 Recent Arctic amplification and
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and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
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Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
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Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
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ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
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de Boer G W Chapman J Kay B Medeiros M D Shupe
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De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
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Dorsey H G Jr 1945 Some meteorological aspects of the
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Douglass A P Newman and S Solomon 2014 The Antarctic
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DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
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R Osinski and A Roberts 2016 Winter atmospheric buoy-
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around southeasternGreenland in theRegionalArctic System
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doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
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Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
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315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
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httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
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in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
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1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
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httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Summer snowfall impact on the Greenland Ice Sheet Cryo-
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
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mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
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by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
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Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
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Rodionov S N J E Overland and N A Bond 2005 The
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Rusin N P 1964 Meteorological and Radiational Regime of
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Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
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Screen J A and I Simmonds 2010 The central role of diminishing
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
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Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
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Taylor P C M Cai A Hu J Meehl W Washington and G J
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Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Thomson A 1948 The growth of meteorological knowledge of
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ThorndikeA S andRColony 1981ArcticOceanBuoy Program
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Timmermans M L J Toole and R Krishfield 2018Warming of the
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Centre sea ice and sea surface temperature data set version 2
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
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mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
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Tomas R A C Deser and L Sun 2016 The role of ocean heat
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Tyson G E and H W Howgate 1879 The Cruise of the Florence
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Untersteiner N A S Thorndike D A Rothrock and K L
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CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
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1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
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van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
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THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
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circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
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Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
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von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
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mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
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Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
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Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
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Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
oceanography of the Bering Sea is dealt with in more
detail in Dallrsquos subsequent work
In his Report on the Currents and Temperatures of Be-
ring Sea and the Adjacent Waters Dall (1882) turned his
attention to questions that are still relevant today What
ocean currents pass between the Pacific Ocean into the
Bering Sea and thence into the Arctic by way of Bering
Strait or from the Arctic to the south What are the
temperatures of these currents and what effect do they
have on the climate including the distribution of sea ice
As he did in his work on meteorology for the Coast Pilot
Dall scoured the literature (and primary sources) from
around the world for data and collected new oceano-
graphic observations as well in his role as assistant-in-
charge of the Coast Survey vessels Yukon and Humbolt
Of particular note is the hydrographic transect of the
Bering Strait completed in 1880 likely the first ever ob-
tained (Fig 21-5) In part the motivation for the transect
was to test the hypothesis that a branch of the warmKuro
Siwo (Kuroshio) passed through Bering Strait creating
a lsquolsquothermometric gatewayrsquorsquo (Bent 1872) that the USS
Jeannette would have followed into the Arctic At the
same time the USRC (Revenue Cutter) Corwin was
searching the area around Wrangel Island for signs of the
missing ship last seen the previous September in the ice
near Herald Island (Hooper 1881) Unbeknownst to both
Dall and Captain Hooper of the Corwin Commander De
Long and the officers of the Jeannette had already ex-
ploded two of the prevailing myths that inspired their
expedition there was no such thing as a thermometric
gateway andWrangel Land was an island and not a large
landmass extending across the Arctic (De Long 1884)
Dallrsquos hydrographic transect combined with the gen-
eral survey of the region yielded a number of particular
insights He found that the current through the Bering
Strait is mainly to the north although reversible by the
wind and that the northward flow is around 1 ft s21mdash
corresponding to a total flow of 42289425 ft3 s21 (12 Sv
1 Sv [ 106 m3 s21) which corresponds well to modern
measurements (eg Woodgate et al 2005) The tempera-
ture structure resolved by theYukon transect in September
shows the warm Alaska Coastal Current (ACC) on the
FIG 21-5 (top)Map of the Bering Strait region showing surface isotherms and sea ice observed by the US Coast Survey schoonerYukon
in AugustSeptember 1880 and (bottom) the hydrographic section obtained on 5 September 1880 (Dall 1882)
CHAPTER 21 WAL SH ET AL 217
eastern side of the strait and the cold Siberian Coastal
Current (Weingartner et al 1999) on the western side The
presence of sea ice at East Cape and southward seems
unusual when compared with recent data but this was
once a common occurrence (eg Danske Meteorologiske
Institut 1900ndash1939 1946ndash1956)Otherwise the temperature
range found by Dall is fairly typical As to the source of
ocean heat present in the region Dall observed that it was
primarily due to local solar radiation rather than to heat
transported into the area from the Pacific Ocean as sug-
gested by Bent (1872) a result consistent with the recent
findings by Timmermans et al (2018)
b The first International Polar Year
The first IPY is notable as the first attempt to extend
a wide meteorological network into the Arctic and
to collect simultaneous observations with similar well-
calibrated instruments and methods The first IPY was
inspired by the Austro-Hungarian naval officer and sci-
entist Karl Weyprecht (Wood and Overland 2006) The
idea for a coordinated international expedition arose from
his experience as co-commander of the Austro-Hungarian
Polar Expedition of 1872ndash74 After returning home he
reflected on the value of the thousands of meteorological
measurements made during the expedition and noted
But whatever interest all these observations may possessthey do not possess that scientific value even supported bya long column of figures which under other circumstancesmight have been the case They only furnish us with apicture of the extreme effects of the forces of Nature in theArctic regions but they leave us completely in the darkwith respect to their causes (Weyprecht 1875)
To answer that question he understood that large-scale
synchronous data collection was required just as it is now
Weyprechtrsquos address to a meeting of German naturalists
and physicians in 1875 included an enduring assessment
lsquolsquoThe entire meteorology of our day rests upon compari-
son All the successes of which it can boastmdashthe laws of
storms the theories of windsmdashare the result of synchro-
nous observationsrsquorsquo (Wood and Overland 2006)
The Second International Meteorological Congress
held inRome in 1879 supportedWeyprechtrsquos conception
of a coordinated international polar research effort and
established a commission to put it into effect It was to be
as Abbe (1893) described it lsquolsquoa simultaneous invasion of
the polar regions from all sidesrsquorsquo International partici-
pation was invited and in due course 11 nations estab-
lished 14 polar research stations 12 in the Arctic and two
in the subantarctic A number of auxiliary stations were
also established including several in Alaska Participa-
tion by the United States was the responsibility of the
Army Signal Service which established two stations one
at Lady Franklin Bay Ellesmere Island and another at
Point Barrow Alaska Lieutenant Adolphus W Greely
(an early member of the American Meteorological So-
ciety) took command of the former expedition and
Lieutenant Patrick Henry Ray commanded the latter
The results of the first IPY were mixed Lieutenant
Greelyrsquos expedition to Lady Franklin Bay was marred
by the loss of all but seven members to deprivation and
other causes Abbe (1893) stated that
the large volumes and results of the two Signal Service in-ternational polar stations as well as the work of the Polarisand Florence expeditions have contributed not a little toadvance our knowledge of the immense country lying to thenorth of the United States in fact the great importance ofthis work becomes more and more evident as other gov-ernments publish their own contributions to this year ofcooperative research and thus enable us to take a compre-hensive survey of the atmospheric conditions at that time
The full publication of the synchronous observations
unfortunately took 25 yearsmdashit was not completed until
1910 and the data were never analyzed all together as
Weyprecht had envisioned
The meteorological observations of the first IPY were
recently transcribed digitized and assimilated by modern
retrospective analysis (reanalysis) systems (eg Compo
et al 2011) and in this sense have finally fulfilled their in-
tended purpose (Wood and Overland 2006) The greater
legacy of the first IPY may be that its successful demon-
stration of international collaboration in polar science
carried on to three subsequent iterations the second IPY
of 1932ndash33 the International Geophysical Year (or third
IPY) of 1957ndash58 (IGY) and the recent IPY of 2007ndash09
c Arctic work of the Weather Bureau
The Alaska Section of the Weather Bureau was offi-
cially started in 1898 with the establishment of the Climate
and Crop Service and set up of a first-class weather station
at Sitka under the direction ofHLBall (Ball 1898) From
the end of the Signal Service years until the 1920s much of
the meteorological data for the region was collected by
volunteer observers Aside from the Sitka station 10 new
subsidiary stations were also expected to be operated by
volunteers Henry (1898) also noted lsquolsquoIt is hoped that
those to whom instruments have been issued from time to
time in previous years will also revive their interests and
report to [Ball]rsquorsquo Of 18 volunteer stations listed by Henry
that were issued instruments by the Weather Bureau the
most successful were located at Coal Harbor (1889ndash1911)
and Killisnoo (1881ndash1910) Other efforts were not as suc-
cessful Instruments sent to observers in the Northwest
Territories (Canada) were seized and in another case the
observer a missionary was murdered and the records
218 METEOROLOG ICAL MONOGRAPHS VOLUME 59
were lost Further development by theWeather Bureau in
Alaska in the early twentieth century was spurred by
economic development around the gold rush and the es-
tablishment of radio and cable communications (Jessup
2007) as well as the increased need for aviation weather
services beginning in the 1920s (see Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
The Weather Bureaursquos further contributions to polar
meteorology followed a similar pattern as in previous
years although on very small scale Between 1893 and
1902 Evelyn Briggs Baldwin aWeather Bureau observer
took part in three privately supported Arctic adventures
Pearyrsquos North Greenland Expedition in 1893ndash94 the
SecondWellmanExpedition to Franz Josef Land in 1898ndash
99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02
Thiswould be the only polar activity directly related to the
Weather Bureau until the 1920s (Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
d Early Antarctic observations
While efforts by the United States were focused on
the Arctic important work in the Antarctic was being
carried out especially by other nations Major meteo-
rological studies in Antarctica commenced with two
historical expeditions The first was in conjunction with
Robert F Scottrsquos attempt (1910ndash13) to be the first to
reach the South (geographic) Pole Scottrsquos Party peri-
shed in 1912 on the Ross Ice Shelf after having arrived at
the Pole 1 month after Roald Amundsen The role
played by weather in this tragedy remains controversial
to this day (Solomon 2001 Fogt et al 2017) Detailed
meteorological observations were collected during
1911ndash12 at the base location of Cape Evans on Ross
Island by George C Simpson who later became Di-
rector General of theUnited KingdomrsquosMeteorological
Office The reporting and analysis of the observations
were delayed byWorldWar I but appeared in a series of
volumes published in India (Simpson 1919 1921 1923)
Important was that the analysis suggested the origin of
lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)
which became a prime motivation for the establishment
of Byrd Station (808S 1208W) during the IGY (1957)
Although the observations have not been continuous
the early observations from the Byrd Station location
have enabled recent studies to demonstrate large annual
temperature increases since the IGY 228 6 138C from
1958 to 2010 (Bromwich et al 2013 2014)
The second expedition of major meteorological im-
portance was led by Douglas Mawson (the Australasian
Antarctic Expedition 1911ndash14) whose experiences were
outlined in a well-known book entitled The Home of the
Blizzard (Mawson 1915) In an ironic twist of events
the party came ashore at Cape Denison (678S 14278E)
because there was open water right to the coast providing
easy access for their ship The meteorological records
from 1912ndash13 revealed the most intense sustained wind
regime on Earth (Madigan 1929) The anemometer was
recalibrated because of doubts about the extreme condi-
tions experienced and it now appears that the revision
was overly conservative The uncorrected records reveal
an annual average wind speed of 22 m s21 with over 60
of all hourly wind speed reports falling in the range of 15ndash
30 m s21 (Parish and Walker 2006) The easy summer ac-
cess to the coast was caused by the intense katabatic winds
blowing the sea ice offshore to create coastal polynyas
(MoralesMaqueda et al 2004) and therefore choosing this
location turned out to be an unfortunate choice in retro-
spect A similar sequence of extreme katabatic wind events
was experienced in 1912 by a satellite party of the Scott
Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)
e A modern renaissance in historical climatology
The advent of sparse-input reanalysis and reanalysis-
forcedmodeling and reconstruction techniques in recent
years has brought new interest in data that were col-
lected in the past but never integrated into modern
large-scale datasets [eg the International Compre-
hensive OceanndashAtmosphere Data Set (ICOADS) the
International Surface Pressure Databank (ISPD)] A
surprisingly large amount of marine-meteorological and
sea ice data collected in the polar regions by the US
Navy Revenue Cutter ServiceCoast Guard and other
federal vessels since the 1880s has never been extracted
from primary sources and compiled This deficit how-
ever is steadily being reduced through collaborative
data recovery projects organized under the Atmospheric
Circulation Reconstructions over the Earth (ACRE) ini-
tiative (Allan et al 2011) and with support from citizen-
scientists participating in Old Weather (httpwww
oldweatherorg) and similar projects (Freeman et al 2016)
Of particular note in this regard are the sea ice ob-
servations collected in the nineteenth and early twenti-
eth century Some of these data were used in a few early
studies (eg Page 1900 Simpson 1890) and from 1900
to 1939 as occasional contributions to the Danish Me-
teorological Institutersquos annual publication State of the
Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash
1939 1946ndash1956) This publication remains a primary
source of sea ice data for the period in modern datasets for
example the Hadley Centrersquos Sea Ice and Sea Surface
Temperature Dataset version 2 (Titchner and Rayner
2014 Walsh and Chapman 2001) and reanalyses that as-
similate ice information [eg the European Centre for
Medium-Range Weather Forecasts (ECMWF) twentieth
century reanalysis (ERA-20C) Poli et al 2016] Reanalyses
CHAPTER 21 WAL SH ET AL 219
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Abbe C 1892 Memoir of William Ferrel 1817ndash1891 Biograph-
ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
Bedel B 1954 Les observations meacuteteacuteorologiques de la station
Franccedilaise du Groenland conditions atmospheacuteriques en alti-
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entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
early twentieth-century warming in the ArcticmdashA possible
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Bent S 1872 Thermal Paths to the Pole An Address Delivered
before the St Louis Mercantile Library Association RP
Studley Co 40 pp
Bessels E 1876 Scientific results of the United States Arctic ex-
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Binder H M Boettcher C M Grams H Joos S Pfahl and
H Wernli 2017 Exceptional air mass transport and dy-
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eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg
1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bockstoce J R and D B Botkin 1983 The historical status and re-
duction of thewesternArctic bowheadwhale (Balaenamysticetus)
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ternational Whaling Commission Rep SC32PS16 107ndash141 pp
httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
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1993 Spatial and temporal variations of the intense katabatic
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doiorg1011751520-0442(2004)0173415PMSOTW20CO2
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Climatological aspects of cyclogenesis near Adelie Land
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mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
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Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
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temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
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Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
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cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
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Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
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1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
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nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
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De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
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DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
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R Osinski and A Roberts 2016 Winter atmospheric buoy-
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around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
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Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
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pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
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orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
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7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
eastern side of the strait and the cold Siberian Coastal
Current (Weingartner et al 1999) on the western side The
presence of sea ice at East Cape and southward seems
unusual when compared with recent data but this was
once a common occurrence (eg Danske Meteorologiske
Institut 1900ndash1939 1946ndash1956)Otherwise the temperature
range found by Dall is fairly typical As to the source of
ocean heat present in the region Dall observed that it was
primarily due to local solar radiation rather than to heat
transported into the area from the Pacific Ocean as sug-
gested by Bent (1872) a result consistent with the recent
findings by Timmermans et al (2018)
b The first International Polar Year
The first IPY is notable as the first attempt to extend
a wide meteorological network into the Arctic and
to collect simultaneous observations with similar well-
calibrated instruments and methods The first IPY was
inspired by the Austro-Hungarian naval officer and sci-
entist Karl Weyprecht (Wood and Overland 2006) The
idea for a coordinated international expedition arose from
his experience as co-commander of the Austro-Hungarian
Polar Expedition of 1872ndash74 After returning home he
reflected on the value of the thousands of meteorological
measurements made during the expedition and noted
But whatever interest all these observations may possessthey do not possess that scientific value even supported bya long column of figures which under other circumstancesmight have been the case They only furnish us with apicture of the extreme effects of the forces of Nature in theArctic regions but they leave us completely in the darkwith respect to their causes (Weyprecht 1875)
To answer that question he understood that large-scale
synchronous data collection was required just as it is now
Weyprechtrsquos address to a meeting of German naturalists
and physicians in 1875 included an enduring assessment
lsquolsquoThe entire meteorology of our day rests upon compari-
son All the successes of which it can boastmdashthe laws of
storms the theories of windsmdashare the result of synchro-
nous observationsrsquorsquo (Wood and Overland 2006)
The Second International Meteorological Congress
held inRome in 1879 supportedWeyprechtrsquos conception
of a coordinated international polar research effort and
established a commission to put it into effect It was to be
as Abbe (1893) described it lsquolsquoa simultaneous invasion of
the polar regions from all sidesrsquorsquo International partici-
pation was invited and in due course 11 nations estab-
lished 14 polar research stations 12 in the Arctic and two
in the subantarctic A number of auxiliary stations were
also established including several in Alaska Participa-
tion by the United States was the responsibility of the
Army Signal Service which established two stations one
at Lady Franklin Bay Ellesmere Island and another at
Point Barrow Alaska Lieutenant Adolphus W Greely
(an early member of the American Meteorological So-
ciety) took command of the former expedition and
Lieutenant Patrick Henry Ray commanded the latter
The results of the first IPY were mixed Lieutenant
Greelyrsquos expedition to Lady Franklin Bay was marred
by the loss of all but seven members to deprivation and
other causes Abbe (1893) stated that
the large volumes and results of the two Signal Service in-ternational polar stations as well as the work of the Polarisand Florence expeditions have contributed not a little toadvance our knowledge of the immense country lying to thenorth of the United States in fact the great importance ofthis work becomes more and more evident as other gov-ernments publish their own contributions to this year ofcooperative research and thus enable us to take a compre-hensive survey of the atmospheric conditions at that time
The full publication of the synchronous observations
unfortunately took 25 yearsmdashit was not completed until
1910 and the data were never analyzed all together as
Weyprecht had envisioned
The meteorological observations of the first IPY were
recently transcribed digitized and assimilated by modern
retrospective analysis (reanalysis) systems (eg Compo
et al 2011) and in this sense have finally fulfilled their in-
tended purpose (Wood and Overland 2006) The greater
legacy of the first IPY may be that its successful demon-
stration of international collaboration in polar science
carried on to three subsequent iterations the second IPY
of 1932ndash33 the International Geophysical Year (or third
IPY) of 1957ndash58 (IGY) and the recent IPY of 2007ndash09
c Arctic work of the Weather Bureau
The Alaska Section of the Weather Bureau was offi-
cially started in 1898 with the establishment of the Climate
and Crop Service and set up of a first-class weather station
at Sitka under the direction ofHLBall (Ball 1898) From
the end of the Signal Service years until the 1920s much of
the meteorological data for the region was collected by
volunteer observers Aside from the Sitka station 10 new
subsidiary stations were also expected to be operated by
volunteers Henry (1898) also noted lsquolsquoIt is hoped that
those to whom instruments have been issued from time to
time in previous years will also revive their interests and
report to [Ball]rsquorsquo Of 18 volunteer stations listed by Henry
that were issued instruments by the Weather Bureau the
most successful were located at Coal Harbor (1889ndash1911)
and Killisnoo (1881ndash1910) Other efforts were not as suc-
cessful Instruments sent to observers in the Northwest
Territories (Canada) were seized and in another case the
observer a missionary was murdered and the records
218 METEOROLOG ICAL MONOGRAPHS VOLUME 59
were lost Further development by theWeather Bureau in
Alaska in the early twentieth century was spurred by
economic development around the gold rush and the es-
tablishment of radio and cable communications (Jessup
2007) as well as the increased need for aviation weather
services beginning in the 1920s (see Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
The Weather Bureaursquos further contributions to polar
meteorology followed a similar pattern as in previous
years although on very small scale Between 1893 and
1902 Evelyn Briggs Baldwin aWeather Bureau observer
took part in three privately supported Arctic adventures
Pearyrsquos North Greenland Expedition in 1893ndash94 the
SecondWellmanExpedition to Franz Josef Land in 1898ndash
99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02
Thiswould be the only polar activity directly related to the
Weather Bureau until the 1920s (Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
d Early Antarctic observations
While efforts by the United States were focused on
the Arctic important work in the Antarctic was being
carried out especially by other nations Major meteo-
rological studies in Antarctica commenced with two
historical expeditions The first was in conjunction with
Robert F Scottrsquos attempt (1910ndash13) to be the first to
reach the South (geographic) Pole Scottrsquos Party peri-
shed in 1912 on the Ross Ice Shelf after having arrived at
the Pole 1 month after Roald Amundsen The role
played by weather in this tragedy remains controversial
to this day (Solomon 2001 Fogt et al 2017) Detailed
meteorological observations were collected during
1911ndash12 at the base location of Cape Evans on Ross
Island by George C Simpson who later became Di-
rector General of theUnited KingdomrsquosMeteorological
Office The reporting and analysis of the observations
were delayed byWorldWar I but appeared in a series of
volumes published in India (Simpson 1919 1921 1923)
Important was that the analysis suggested the origin of
lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)
which became a prime motivation for the establishment
of Byrd Station (808S 1208W) during the IGY (1957)
Although the observations have not been continuous
the early observations from the Byrd Station location
have enabled recent studies to demonstrate large annual
temperature increases since the IGY 228 6 138C from
1958 to 2010 (Bromwich et al 2013 2014)
The second expedition of major meteorological im-
portance was led by Douglas Mawson (the Australasian
Antarctic Expedition 1911ndash14) whose experiences were
outlined in a well-known book entitled The Home of the
Blizzard (Mawson 1915) In an ironic twist of events
the party came ashore at Cape Denison (678S 14278E)
because there was open water right to the coast providing
easy access for their ship The meteorological records
from 1912ndash13 revealed the most intense sustained wind
regime on Earth (Madigan 1929) The anemometer was
recalibrated because of doubts about the extreme condi-
tions experienced and it now appears that the revision
was overly conservative The uncorrected records reveal
an annual average wind speed of 22 m s21 with over 60
of all hourly wind speed reports falling in the range of 15ndash
30 m s21 (Parish and Walker 2006) The easy summer ac-
cess to the coast was caused by the intense katabatic winds
blowing the sea ice offshore to create coastal polynyas
(MoralesMaqueda et al 2004) and therefore choosing this
location turned out to be an unfortunate choice in retro-
spect A similar sequence of extreme katabatic wind events
was experienced in 1912 by a satellite party of the Scott
Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)
e A modern renaissance in historical climatology
The advent of sparse-input reanalysis and reanalysis-
forcedmodeling and reconstruction techniques in recent
years has brought new interest in data that were col-
lected in the past but never integrated into modern
large-scale datasets [eg the International Compre-
hensive OceanndashAtmosphere Data Set (ICOADS) the
International Surface Pressure Databank (ISPD)] A
surprisingly large amount of marine-meteorological and
sea ice data collected in the polar regions by the US
Navy Revenue Cutter ServiceCoast Guard and other
federal vessels since the 1880s has never been extracted
from primary sources and compiled This deficit how-
ever is steadily being reduced through collaborative
data recovery projects organized under the Atmospheric
Circulation Reconstructions over the Earth (ACRE) ini-
tiative (Allan et al 2011) and with support from citizen-
scientists participating in Old Weather (httpwww
oldweatherorg) and similar projects (Freeman et al 2016)
Of particular note in this regard are the sea ice ob-
servations collected in the nineteenth and early twenti-
eth century Some of these data were used in a few early
studies (eg Page 1900 Simpson 1890) and from 1900
to 1939 as occasional contributions to the Danish Me-
teorological Institutersquos annual publication State of the
Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash
1939 1946ndash1956) This publication remains a primary
source of sea ice data for the period in modern datasets for
example the Hadley Centrersquos Sea Ice and Sea Surface
Temperature Dataset version 2 (Titchner and Rayner
2014 Walsh and Chapman 2001) and reanalyses that as-
similate ice information [eg the European Centre for
Medium-Range Weather Forecasts (ECMWF) twentieth
century reanalysis (ERA-20C) Poli et al 2016] Reanalyses
CHAPTER 21 WAL SH ET AL 219
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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Bryson R A 1966 Air masses stream lines and the boreal forest
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Cassano J J J E Box D H Bromwich L Li and K Steffen
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Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
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mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
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mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
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doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
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Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
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1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
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101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
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English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
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Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
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(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
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Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
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Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
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McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
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Page J 1900 Ice and ice movements in Bering Sea during the
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Palmeacuten E 1951 The role of atmospheric disturbances in the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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CHAPTER 21 WAL SH ET AL 2133
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
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mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
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s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
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Screen J A and I Simmonds 2010 The central role of diminishing
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mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
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mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
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Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
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1913 Meteorology Thacker Spink amp Company 355 pp
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1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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measurements of the springtime Antarctic ozone decrease
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Strahan S E and A R Douglass 2018 Decline in Antarctic
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from Aura Microwave Limb Sounder observations Geophys
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
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Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
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Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
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doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Southern Hemisphere surface climate change Nat Geosci 4
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Thomson A 1948 The growth of meteorological knowledge of
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arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
were lost Further development by theWeather Bureau in
Alaska in the early twentieth century was spurred by
economic development around the gold rush and the es-
tablishment of radio and cable communications (Jessup
2007) as well as the increased need for aviation weather
services beginning in the 1920s (see Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
The Weather Bureaursquos further contributions to polar
meteorology followed a similar pattern as in previous
years although on very small scale Between 1893 and
1902 Evelyn Briggs Baldwin aWeather Bureau observer
took part in three privately supported Arctic adventures
Pearyrsquos North Greenland Expedition in 1893ndash94 the
SecondWellmanExpedition to Franz Josef Land in 1898ndash
99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02
Thiswould be the only polar activity directly related to the
Weather Bureau until the 1920s (Encyclopedia Arctica
1947ndash51 httpscollectionsdartmoutheduarctica-beta)
d Early Antarctic observations
While efforts by the United States were focused on
the Arctic important work in the Antarctic was being
carried out especially by other nations Major meteo-
rological studies in Antarctica commenced with two
historical expeditions The first was in conjunction with
Robert F Scottrsquos attempt (1910ndash13) to be the first to
reach the South (geographic) Pole Scottrsquos Party peri-
shed in 1912 on the Ross Ice Shelf after having arrived at
the Pole 1 month after Roald Amundsen The role
played by weather in this tragedy remains controversial
to this day (Solomon 2001 Fogt et al 2017) Detailed
meteorological observations were collected during
1911ndash12 at the base location of Cape Evans on Ross
Island by George C Simpson who later became Di-
rector General of theUnited KingdomrsquosMeteorological
Office The reporting and analysis of the observations
were delayed byWorldWar I but appeared in a series of
volumes published in India (Simpson 1919 1921 1923)
Important was that the analysis suggested the origin of
lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)
which became a prime motivation for the establishment
of Byrd Station (808S 1208W) during the IGY (1957)
Although the observations have not been continuous
the early observations from the Byrd Station location
have enabled recent studies to demonstrate large annual
temperature increases since the IGY 228 6 138C from
1958 to 2010 (Bromwich et al 2013 2014)
The second expedition of major meteorological im-
portance was led by Douglas Mawson (the Australasian
Antarctic Expedition 1911ndash14) whose experiences were
outlined in a well-known book entitled The Home of the
Blizzard (Mawson 1915) In an ironic twist of events
the party came ashore at Cape Denison (678S 14278E)
because there was open water right to the coast providing
easy access for their ship The meteorological records
from 1912ndash13 revealed the most intense sustained wind
regime on Earth (Madigan 1929) The anemometer was
recalibrated because of doubts about the extreme condi-
tions experienced and it now appears that the revision
was overly conservative The uncorrected records reveal
an annual average wind speed of 22 m s21 with over 60
of all hourly wind speed reports falling in the range of 15ndash
30 m s21 (Parish and Walker 2006) The easy summer ac-
cess to the coast was caused by the intense katabatic winds
blowing the sea ice offshore to create coastal polynyas
(MoralesMaqueda et al 2004) and therefore choosing this
location turned out to be an unfortunate choice in retro-
spect A similar sequence of extreme katabatic wind events
was experienced in 1912 by a satellite party of the Scott
Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)
e A modern renaissance in historical climatology
The advent of sparse-input reanalysis and reanalysis-
forcedmodeling and reconstruction techniques in recent
years has brought new interest in data that were col-
lected in the past but never integrated into modern
large-scale datasets [eg the International Compre-
hensive OceanndashAtmosphere Data Set (ICOADS) the
International Surface Pressure Databank (ISPD)] A
surprisingly large amount of marine-meteorological and
sea ice data collected in the polar regions by the US
Navy Revenue Cutter ServiceCoast Guard and other
federal vessels since the 1880s has never been extracted
from primary sources and compiled This deficit how-
ever is steadily being reduced through collaborative
data recovery projects organized under the Atmospheric
Circulation Reconstructions over the Earth (ACRE) ini-
tiative (Allan et al 2011) and with support from citizen-
scientists participating in Old Weather (httpwww
oldweatherorg) and similar projects (Freeman et al 2016)
Of particular note in this regard are the sea ice ob-
servations collected in the nineteenth and early twenti-
eth century Some of these data were used in a few early
studies (eg Page 1900 Simpson 1890) and from 1900
to 1939 as occasional contributions to the Danish Me-
teorological Institutersquos annual publication State of the
Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash
1939 1946ndash1956) This publication remains a primary
source of sea ice data for the period in modern datasets for
example the Hadley Centrersquos Sea Ice and Sea Surface
Temperature Dataset version 2 (Titchner and Rayner
2014 Walsh and Chapman 2001) and reanalyses that as-
similate ice information [eg the European Centre for
Medium-Range Weather Forecasts (ECMWF) twentieth
century reanalysis (ERA-20C) Poli et al 2016] Reanalyses
CHAPTER 21 WAL SH ET AL 219
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
REFERENCES
Abbe C 1892 Memoir of William Ferrel 1817ndash1891 Biograph-
ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
tion Reconstructions over the Earth (ACRE) Initiative Bull
Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
2011BAMS32181
Anderson R B Bolville and D E McClellan 1955 An opera-
tional frontal contour analysis model Quart J Roy Meteor
Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
ternational Polar Years (IPYs) From Pole to Pole Vol 1
Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
covery 1776ndash1880 Part 1 Journals of Captain James Cook on his
Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
Bedel B 1954 Les observations meacuteteacuteorologiques de la station
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tude (Meteorological observations of the French Greenland
station atmospheric conditions at altitude) Expeacuteditions Po-laires Franccedilaises Missions Paul-Emile Victor Resultats Sci-
entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
early twentieth-century warming in the ArcticmdashA possible
mechanism J Climate 17 4045ndash4057 httpsdoiorg1011751520-0442(2004)0174045TETWIT20CO2
Bent S 1872 Thermal Paths to the Pole An Address Delivered
before the St Louis Mercantile Library Association RP
Studley Co 40 pp
Bessels E 1876 Scientific results of the United States Arctic ex-
pedition Steamer Polaris CF Hall commanding US Navy
Rep Government Printing Office 986 pp httpsarchive
orgdetailscu31924029881095pagen5
Binder H M Boettcher C M Grams H Joos S Pfahl and
H Wernli 2017 Exceptional air mass transport and dy-
namical drivers of an extreme wintertime Arctic warm
eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg
1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
bridge University Press 867ndash952
Bockstoce J R and D B Botkin 1983 The historical status and re-
duction of thewesternArctic bowheadwhale (Balaenamysticetus)
population by the pelagic whaling industry 1848ndash1914 In-
ternational Whaling Commission Rep SC32PS16 107ndash141 pp
httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
katabatic winds and the Terra Nova Bay polynya Polar Rec
21 137ndash146 httpsdoiorg101017S0032247400004514
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and NCEPNCAR reanalyses in the high and middle latitudes
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1993 Spatial and temporal variations of the intense katabatic
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and Climatology Studies Based on Automatic Weather Sta-
tions D H Bromwich and C R Stearns Eds Antarctic
Research Series Vol 61 Amer Geophys Union 47ndash68
mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
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Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
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mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
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4189ndash4209 httpsdoiorg1011752011JCLI40741
mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
arctica among the most rapidly warming regions on Earth
Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash and mdashmdash 2014 Corrigendum
Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
changing climate Environ Res Lett 10 025003 httpsdoiorg
1010881748-9326102025003
2130 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
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3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
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doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
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1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
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mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
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(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
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orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
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Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
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Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
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mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
require a good characterization of the ice edge to establish
appropriate boundary conditions Moreover more com-
plete recovery of available ice observations provides an
invaluable baseline reference to understand the dramatic
loss of sea ice taking place in the Arctic today Ice obser-
vations from whaling ships for the period 1850ndash1913 have
been extracted (Bockstoce and Botkin 1983 Mahoney
et al 2011) and compiled into a sea ice dataset the His-
torical Sea IceAtlas (Walsh et al 2016) However the data-
rich federal logbooks have only recently been addressed
comprehensively by Old Weather citizen-scientists and
applied in current research (Schweiger et al 2018 manu-
script submitted to J Geophys Res Oceans) Thus thou-
sands of sea ice observations frommore than a century ago
have been gleaned from the logbooks of the Bear Corwin
Thetis Northland and other federal vessels and are being
put to new uses that were unimaginable to the officers who
originally recorded them (Fig 21-6)
3 From 1919 to the 1940s
Systematic aircraft-based observations of the Arctic
began in 1929 when the Soviet Polar Aircraft Fleet was
created (Polyakov et al 2003) The 1920s also saw reports
of a loss of sea ice in the subpolar North Atlantic Ocean
together with early conjectures that reduced sea ice cov-
erage should contribute to changes in cyclone activity
(Wiese 1924) In a report that would not have been out of
place in the early 2000s the American consul in Bergen
Norway provided the following report to the US State
Department in October of 1922
The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)
a Second International Polar Year (1932ndash33)
Increased interest in the Arctic during this period led
to the second IPY held in 1932ndash33 A major goal was to
FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum
Northwest)
2110 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
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Bent S 1872 Thermal Paths to the Pole An Address Delivered
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Binder H M Boettcher C M Grams H Joos S Pfahl and
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Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bockstoce J R and D B Botkin 1983 The historical status and re-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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1993 Spatial and temporal variations of the intense katabatic
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Hughes 2004 Polar MM5 simulations of the winter climate of the
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precipitation changes over Antarctica and the Southern Ocean
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mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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1010881748-9326102025003
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
investigate how observations in the polar regions could
improve the accuracy of weather forecasts and as a
result the safety of air and sea transport The second
IPY was also motivated in part by the recognition
that the electromagnetic processes in the polar regions
were affecting telegraph telephone and electric power
lines In addition the availability of new instruments
such as the radiosonde as well as aircraft and motorized
vehicles for sea and land transport provided new op-
portunities for measurements including below the
surface Altogether a total of 94 meteorological sta-
tions operated in the Arctic for at least part of the
second IPY (Laursen 1959) This period provided the
first systematic upper-air measurements in the Arctic
by radiosonde and pilot balloons Plans for a network
of Antarctic stations never came to fruition because of
the global financial crisis of the 1930s In the summer of
1932 the Russian icebreaker Sibriyakov completed a
transit of the Northern Sea Route from Arkhangelsk
to the Far East (Barr 1978) Although World War II
prevented the planned archival of all the data at the
Danish Meteorological Institute much of the data
eventually found its way into a world data center that
was created under an organization that eventually be-
came known as the World Meteorological Organiza-
tion (Barr and Luumldecke 2010)
b Russian North Pole stations
A major milestone of the period between the two
world wars was the Soviet Unionrsquos establishment of the
first North Pole Drifting Station (NP-1) Established on
pack ice near the North Pole in May of 1937 the ice
station drifted more than 2800 km before its abandon-
ment 9 months later This was the first of many such
stations (from NP-1 through NP-31) deployed by the
Russians prior to the breakup of the Soviet Union
A resumption of deployments in 2003 has included sta-
tions from NP-32 through NP-40 These stations occu-
pied for periods typically ranging from several seasons
to several years provided the first multiyear records of
atmospheric oceanic and sea ice variables from the
central Arctic Ocean In addition to standard surface
and upper-air (sounding) meteorological observations
at regular intervals each day the NP stations provided
surface radiation (solar longwave and spectral albedo)
measurements total ozone andUVmeasurements teth-
ered balloon measurements in the lowest 2 km and at-
mospheric composition measurements These data are
invaluable in the construction of twentieth-century cli-
matologies for atmospheric variables as well as snow and
ice thickness The NP data have also been widely used in
the validation of historical simulations of the central
Arctic Ocean by global and regional climate models (as
well as atmospheric reanalyses) Much of our early
knowledge of the surface energy budget of the central
Arctic Ocean was built on surface flux measurements
made at NP stations (eg Fletcher 1965) as was in-
formation on cloud conditions (eg Vowinckel and
Orvig 1971) and cloud radiative forcing Even after the
first stage of NP observations ended in the early 1990s
the NP measurements formed the basis for studies of
surfacendashatmosphere interactions in the Arctic Ocean
For example NP data showed that cloud-radiative
forcing is negative for two to three months in the sum-
mer with a strong dependence of the surface radiative
fluxes on cloud fraction (Walsh and Chapman 1998)
Although the second IPY targeted Arctic observa-
tions and measurements to improve forecasts the 1930s
also saw the first attempts to document and understand
understanding the warming of the Arctic during the
1920s and 1930s The Ifft (1922) report was among the
first to point to this notable climate event As shown in
Fig 21-7 the early twentieth-century Arctic warming
was followed by several decades of cooling then by the
strong warming of recent decades These variations are
apparent in the global as well as the Arctic time series of
Fig 21-7 which illustrates the tendency for variations of
global temperature to be amplified in the Arctic (section
5i) While various recent studies have placed the early
twentieth-century warming into a framework of climate
drivers several notable observational reports and di-
agnostic studies addressed the warming while it was
ongoing or shortly thereafter Scherhag (1936) noted
that warming of the North Atlantic Subarctic region was
accompanied by a retreat of sea ice that was consistent
with anomalous wind forcing in the region A role of the
FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-
perature anomaly averaged over 608ndash908N (blue curve) and the
globe (red curve) Anomalies are relative to corresponding means
for 1980ndash2010 Both the Arctic and the global time series are based
on surface air temperature measurements from land stations ar-
chived in the CRUTEM4 dataset (httpscrudataueaacukcru
datatemperature) [Source after Fig 1 fromOverland et al (2017)
see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_
full_report2017pdf]
CHAPTER 21 WAL SH ET AL 2111
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
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1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
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doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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The Physical Science Basis T F Stocker et al Eds Cam-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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Climatological aspects of cyclogenesis near Adelie Land
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Central West Antarctica among the most rapidly warming
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ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
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Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
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over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
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Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
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mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
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of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
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mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
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Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
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changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
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Screen J A and I Simmonds 2010 The central role of diminishing
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
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Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
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Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
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Taylor P C M Cai A Hu J Meehl W Washington and G J
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Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
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ThompsonDW J and S Solomon 2002 Interpretation of recent
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Thomson A 1948 The growth of meteorological knowledge of
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ThorndikeA S andRColony 1981ArcticOceanBuoy Program
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Timmermans M L J Toole and R Krishfield 2018Warming of the
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Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
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Centre sea ice and sea surface temperature data set version 2
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
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mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
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Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
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JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
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Untersteiner N A S Thorndike D A Rothrock and K L
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Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
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CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
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1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
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van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
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THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
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von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
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mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
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Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
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Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
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Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
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schaftlichen Beobachtungen gehalten in Wien 18 Januar
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Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
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Wilkes C 1845a Narrative of the United States Exploring Ex-
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Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
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Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
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Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
ocean including a shoaling of the halocline (eerily similar
to discussions of Arctic Ocean change in the past few de-
cades) was proposed byBrooks (1938) Carruthers (1941)
andManley (1944) The SecondWorldWar led to a hiatus
in the debate about the Arcticrsquos early twentieth-century
warming However interest resurfaced in the early
twenty-first century (eg Bengtsson et al 2004Wood and
Overland 2010 Yamanouchi 2011) While there is evi-
dence that internal variability played a key role in the early
twentieth-century warming (Fyfe et al 2013) there is still
debate about the precise roles of the atmospheric circu-
lation and the ocean The most recent IPCC assessment
(AR5) explicitly states lsquolsquoThere is still considerable dis-
cussion of the ultimate causes of the warm temperature
anomalies that occurred in the Arctic in the 1920s and
1930srsquorsquo (Bindoff et al 2013 p 907)
4 From the 1940s to the 1970s (the Cold Warperiod)
a The Second World War
The Second World War led to rapid expansion of
meteorological services In 1939 the focus in Canada
was to meet the growing needs of Trans-Canada Air-
lines The onset of war brought added needs especially
to support the Royal Canadian Air Force (RCAF) the
British Commonwealth Air Training Plan and the US
Army Air Force for ferrying activities over the Atlantic
Ocean and to Alaska In northern Canada the United
States assisted in establishing observing stations and
forecast offices (Thomson 1948 Thomas 1971) Starting
in 1940 after the German occupation of Denmark a
number of stations were set up along the coast of Green-
land these included weather stations in places like Thule
and Scoresbysund This action resulted from an agreement
with the Danish Ambassador of Denmark for the United
States to defend Danish colonies in Greenland In 1941
when Germany attacked the Soviet Union the Barents
Sea gained great strategic importance leading to a series
of efforts by Germany the United Kingdom and Norway
to gain control of Svalbard critically situated to pro-
vide data for forecasting weather in central Europe and
for attacking Atlantic convoys headed for Murmansk
Russia In this lsquolsquowar forweatherrsquorsquo theGermans established
several secret stations in Svalbard as well as in north-
eastern Greenland and Franz Josef Land (httpswww
spitsbergen-svalbardcom)
b Early work on Greenland
From September 1949 to August 1951 the meteorol-
ogists of the French Polar Expeditions under the di-
rection of Paul-Emile Victor carried out soundings of
wind and temperature on Greenland at Station Centrale
(7098N 4068W 2965 m elevation) (eg Bedel 1954)
The station near the location of Alfred Wegenerrsquos
lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of
the crest of the ice sheet Analysis of profiles collected
under strong temperature inversion conditions allowed
Schwerdtfeger (1972) to infer that the sloped-inversion
pressure gradient force arising from the presence of cold
air over sloping terrain which was developed to explain
the behavior of the wind field in the high interior of
Antarctica also applied to interior Greenland indicating
that the governing dynamics were the same
c Early work on Antarctica
Following the historical Antarctic expeditions in the
early 1900s meteorological studies entered a period
with slow progress Richard E Byrd led three expedi-
tions to Little America on the eastern edge of the Ross
Ice Shelf starting with the base location to stage the first
aircraft flight over the South Pole in 1929 All of these
featured extensive meteorological programs that in-
cluded upper-air observations Perhaps the most im-
portant advance came in 1946 before the US Navy was
demobilized afterWorldWar II The 1946ndash47US Navy
Antarctic Expedition designated as Operation High-
jump (Byrd 1947) was conceived to map almost the
entire periphery of the Antarctic continent for the first
time Led by Rear Admiral Byrd it involved many navy
ships and aircraft This information and the associated
photographs helped to set the stage for establishing the
network of Antarctic coastal stations for the 18-month
(1957ndash58) IGY which marked the start of sustained
instrumental observations from Antarctica and thus the
beginning of many climatic records from this remote
continent
d Glacial anticyclones
While the need for climate and weather information
over the North Atlantic and Alaska remained critical
throughout the war the climate and weather of the cen-
tral Arctic remained understudied and data were sparse
A persistent viewwas of anArctic Ocean dominated by a
largely permanent anticyclonic cell First put forth by von
Helmholtz (1888) the idea was elaborated on by Hobbs
(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and
subsequently gained traction Jones (1987) notes that
charts from the US Historical Weather Map Series
prepared during the Second World War contained con-
siderable positive pressure biases over the Arctic Ocean
up to 1930 and lesser errors up to 1939 It seems that these
maps were compiled by relatively untrained analysts ex-
trapolating pressures into the data-poor central Arctic
with the preconceived notion of a high pressure cell
2112 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
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doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
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Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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Binder H M Boettcher C M Grams H Joos S Pfahl and
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1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bockstoce J R and D B Botkin 1983 The historical status and re-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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Hughes 2004 Polar MM5 simulations of the winter climate of the
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httpsdoiorg1010292008JD010300
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Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
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mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
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over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
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Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
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1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
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physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
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mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
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Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
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measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
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httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo
theory (Hobbs 1945) involving a persistent high pressure
cell over the Greenland ice sheet with strong influences
on weather inmidlatitudes Although other investigations
found little support for the idea (Loewe 1936 Dorsey
1945 Matthes 1946 Matthes and Belmont 1950) the
thinking of anticyclones as dominant features of the cen-
tral Arctic Ocean persisted (eg Pettersen 1950 Rae
1951) Pettersenrsquos (1950) maps depict most of the Arctic
Ocean in both summer and winter as a lsquolsquoquiet zone of
minimum cyclonic activityrsquorsquo Such views may have been
influenced by Otto Sverdruprsquos observations during the
Maud expedition (1918ndash25) of the frequent passage of
cyclones along the fringes of the Arctic Ocean
e The growing data network
With the deployment of a series of the Soviet NP
drifting stations on the Artic sea ice US drifting sta-
tions the Ptarmigan series of aircraft overflights the
establishment of weather stations in the Canadian
Arctic and studies prompted by the IGY in 1957 the
observing network started to improve A key need was
better coverage over the Arctic Ocean The Soviet NP-2
station led by Mikhail Mikhailovich Somov (Hero of
the Soviet Union and recipient of three Orders of
Lenin) was deployed in April of 1950 and NP-3 as-
sumed duties in 1954 Starting in 1954 from one to three
NP stations began operating simultaneously each year
collecting meteorological data of all types including at-
mospheric soundings from radiosondes The United
States maintained a number of drifting stations notably
T-3 (also called Fletcherrsquos Ice Island named after Col-
onel Joseph O Fletcher who discovered it) Starting in
1952 T-3 was used as a scientific drift station and in-
cluded huts a power plant and a runway for wheeled
aircraft T-3 was a tabular iceberg that presumably broke
off from the small ice shelves along the northern coast of
Ellesmere Island The NP Stations were located variously
on ice islands (tabular icebergs) and thick floes of sea ice
Ptarmigan was a series of aircraft reconnaissance missions
conducted by theUSAir Force over the period from1950
to 1961 The missions included collecting soundings in the
lower troposphere over theArcticOcean fromdropsondes
that descended by parachute (Kahl et al 1992)
In terms of land-based stations Eureka on Ellesmere
Island then part of the Northwest Territories Canada
was established in April of 1947 Weather station Alert
on the northern end of Ellesmere Island was established
in 1950 and a military station was set up in 1958 The
station is named after the HMS Alert which wintered
near the site of the station in 1875ndash76 The community at
Resolute Bay on Cornwallis Island was created in 1953
as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was
an effort by Canada to assert sovereignty in the high
Arctic because of the regionrsquos perceived strategic im-
portance As part of this effort the Canadian Govern-
ment forcibly relocated Inuit from northern Quebec to
Resolute (and to Grise Fiord) By 1947 Canada and the
United States had already built a weather station at
Resolute as well as an airstrip This was followed in
1949 by the establishments of a Royal Canadian Air
Force base
Another major driver of the improved observational
network in Canada was the establishment during the
1950s of the Distant Early Warning (DEW) Line
(Fig 21-8) The DEW Line was a system of radar sta-
tions installed in a line across Arctic Canada (some at
existing villages such as at Cambridge Bay in 1955)
intended to provide early warning of a Soviet bomber
attack Additional stations were built along the northern
coastline and Aleutian Islands of Alaska as well as in
Greenland Iceland and the Faroe Islands
f Evolving thought
FollowingWorldWar II two major Canadian research
groups emerged at McGill University a radar meteorol-
ogy group led by J Stewart Marshall and R H Douglas
in the Department of Physics and an Arctic meteorology
group within the Department of Geography led by F K
Hare The two groups merged in 1959 to form the De-
partment of Meteorology McGill became a dominant
force in studies of Arctic meteorology and climate during
this period By 1958 (before themerger) theMcGill Arctic
meteorology research group had already published a
number of key reports on Arctic meteorology that took
advantage of the growing observational network (eg
Wilson 1958 Hare and Orvig 1958)
However it is noteworthy that in the Soviet Union a
mature viewof the circulationover the centralArcticOcean
had emerged as early as 1945 In a remarkable accom-
plishment especially given the very trying wartime con-
ditions Dzerdzeevskii (1945) correctly concluded that
cyclone activity was common in the central Arctic Ocean
especially during summer His study took advantage of
data from the Russian drifting icebreaker Sedov the
drifting ice island NP-1 and other high Arctic stations
(Jones 1987)
Western scientists may have been unaware of this
work indeed even in 1958 the idea of a quiescent
Arctic Ocean persisted in some circles For example
the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is
CHAPTER 21 WAL SH ET AL 2113
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
REFERENCES
Abbe C 1892 Memoir of William Ferrel 1817ndash1891 Biograph-
ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
2011BAMS32181
Anderson R B Bolville and D E McClellan 1955 An opera-
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Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
Bedel B 1954 Les observations meacuteteacuteorologiques de la station
Franccedilaise du Groenland conditions atmospheacuteriques en alti-
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entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
early twentieth-century warming in the ArcticmdashA possible
mechanism J Climate 17 4045ndash4057 httpsdoiorg1011751520-0442(2004)0174045TETWIT20CO2
Bent S 1872 Thermal Paths to the Pole An Address Delivered
before the St Louis Mercantile Library Association RP
Studley Co 40 pp
Bessels E 1876 Scientific results of the United States Arctic ex-
pedition Steamer Polaris CF Hall commanding US Navy
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Binder H M Boettcher C M Grams H Joos S Pfahl and
H Wernli 2017 Exceptional air mass transport and dy-
namical drivers of an extreme wintertime Arctic warm
eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg
1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bockstoce J R and D B Botkin 1983 The historical status and re-
duction of thewesternArctic bowheadwhale (Balaenamysticetus)
population by the pelagic whaling industry 1848ndash1914 In-
ternational Whaling Commission Rep SC32PS16 107ndash141 pp
httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
katabatic winds and the Terra Nova Bay polynya Polar Rec
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mdashmdash and R L Fogt 2004 Strong trends in the skill of the ERA-40
and NCEPNCAR reanalyses in the high and middle latitudes
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mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner
1993 Spatial and temporal variations of the intense katabatic
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and Climatology Studies Based on Automatic Weather Sta-
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Research Series Vol 61 Amer Geophys Union 47ndash68
mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
Hughes 2004 Polar MM5 simulations of the winter climate of the
Laurentide IceSheet at theLGM JClimate17 3415ndash3433 https
doiorg1011751520-0442(2004)0173415PMSOTW20CO2
mdashmdash KM Hines and L-S Bai 2009 Development and testing of
Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
httpsdoiorg1010292008JD010300
mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
since 1989 in contemporary global reanalyses J Climate 24
4189ndash4209 httpsdoiorg1011752011JCLI40741
mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
arctica among the most rapidly warming regions on Earth
Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash and mdashmdash 2014 Corrigendum
Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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1010881748-9326102025003
2130 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)
It is clear however that by the late 1950s there was an
epiphany A series of studies emerged in rapid-fire suc-
cession that form a framework for our modern view of
the Arctic atmospheric circulation As noted by the
pioneering meteorologist Jerome Namias
the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)
Although long-term prediction (a topic of great in-
terest to Namias) has remained an elusive goal the new
data certainly enabled a much better definition of the
structure of the circumpolar vortex and features of the
surface circulation It quickly became clear that while
anticyclones are common and often persistent features
of the Arctic circulation especially in winter and over
land areas cyclones are also frequent and depending
on the season may be found anywhere in the Arctic
(Keegan 1958 Reed and Kunkel 1960) As a sufficient
number of soundings began to reach the 25-hPa level it
became possible to investigate stratospheric dynamics
and the McGill University group played a leading role
(eg Hare 1960ab 1961) as did the Institute of Mete-
orology at the Free University of Berlin under Richard
Scherhag (Scherhag 1960)
Interest grew about the nature of Arctic air masses
andArctic fronts Any synoptic analysis will reveal high-
latitude weather fronts and associated jet streams but
can an Arctic frontal zone separate from the polar
frontal zone be identified Some early studies that were
based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate
high-latitude Arctic frontal zone Nevertheless early
Canadian analysis schemes (Anderson et al 1955
Penner 1955) adopted a three-front model with the
northernmost (in any season) representing individual
Arctic fronts The Meteorological Branch of Canada
prepared routine synoptic charts showing the location of
FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki
Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)
2114 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Allan R P Brohan G Compo R Stone J Luterbacher and
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Meteorology Proceedings of the Symposium in Melbourne
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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Barnes E A and J A Screen 2015 The impact of Arctic
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Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
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Barry R G 1967 Seasonal location of theArctic front over North
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Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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Bindoff N L and Coauthors 2013 Detection and attribution of
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The Physical Science Basis T F Stocker et al Eds Cam-
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httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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and NCEPNCAR reanalyses in the high and middle latitudes
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mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner
1993 Spatial and temporal variations of the intense katabatic
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mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
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doiorg1011751520-0442(2004)0173415PMSOTW20CO2
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Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
httpsdoiorg1010292008JD010300
mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
since 1989 in contemporary global reanalyses J Climate 24
4189ndash4209 httpsdoiorg1011752011JCLI40741
mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash and mdashmdash 2014 Corrigendum
Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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2130 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
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Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
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Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
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Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
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1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
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1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
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Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
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101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
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McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
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mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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mdashmdash and R Walker 2006 A re-examination of the winds of
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Parkinson C L and J C Comiso 2013 On the 2012 record low
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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CHAPTER 21 WAL SH ET AL 2133
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2002 Measurements near the atmospheric surface group
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
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Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
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Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
three fronts on the 850- 700- and 500-hPa levels Using
these data Barry (1967) examined the location of the
Arctic frontal zone over North America for January
April July and October Shapiro et al (1987) more
recently presented clear evidence in winter of Arctic jet
streams with tropopause folds between the lower Arctic
troposphere to the north and the higher Arctic tropo-
sphere to the south These fields are associated with
what are now known as tropopause polar vortices
(Cavallo and Hakim 2009 2010 2012)
A prominent climatological feature of the Arctic
summer is the thermal contrast between the Arctic
Ocean and the surrounding land areas There has long
been interest in the concept of a summer Arctic frontal
zone separate from frontal activity in midlatitudes
Dzerdzeevskii (1945) was the first to present evidence
for its existence Reed and Kunkel (1960) subsequently
looked at the issue in more detail They noted the exis-
tence in summer only of a band of high frontal fre-
quencies extending along the northern shores of Siberia
and Alaska and southeastward across Canada and
stated that it is lsquolsquoabundantly clear that the polar front
remains separate from and well to the south of the
Arctic frontal zonersquorsquo Bryson (1966) demonstrated that
the modal position of the summer Arctic frontal zone
over North America coincided closely with Reed and
Kunkelrsquos (1960) analysis as well as the position of the
tree line This led to a recurring notion of a vegetation
link Bryson (1966) proposed that the summer frontal
position might be important in determining the distri-
bution of forest versus tundra but other investigators
(Hare 1968 Hare and Ritchie 1972) instead argued that
the tundrandashforest boundary actually helps to control the
position of the frontal zone in summer because of con-
trasts in albedo evaporation and aerodynamic rough-
ness However it has now been clearly established that
a primary control on the summer Arctic frontal zone
is differential heating between the land and ocean
(Serreze et al 2001 Crawford and Serreze 2015) an idea
first advanced as early as 1945 by Dzerdzeevskii (1945)
Arctic frontal activity in particular the summerArctic
frontal zone remains an active research area Using an
analog approach Day and Hodges (2018) argue that
because of increasing landndashocean temperature con-
trasts the summer Arctic frontal zone will sharpen and
that Arctic cyclones are likely to become more frequent
and intense as the Arctic continues to warm However
work by Crawford and Serreze (2016) show the summer
Arctic frontal zone is not in itself a region of cyclogen-
esis but rather acts to intensify cyclones that pass
through it Based on coupled climate model simulations
Crawford and Serreze (2017) argue that the frontal zone
will remain a significant cyclone intensifier in the future
but that changes in frontal strength will be largely re-
stricted to June when earlier snowmelt sharpens landndash
ocean temperature contrasts
g NWP and climate models
By the 1940s through the work of Bjerknes Rossby
and others the physical mechanisms controlling weather
processes were fairly well understood enabling some
skill in forecasting which was critical to the wartime
effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts
are a prime example of the importance of meteorology
to the wartime effort However successful numerical
prediction had to await the advent of digital computers
The first successful effort in the United States was in
1950 when a team led by Jule Charney and John
von Neumann used the Electronic Numerical Integrator
and Computer (ENIAC) to solve the barotropic vor-
ticity equation (httpsenwikipediaorgwikiHistory_of_
numerical_weather_prediction) In the United Kingdom
the first numerical model forecast was made in 1952 Op-
erational numerical forecasting in the United States started
in 1955 and the United Kingdom followed suit in 1965
(httpswwwmetofficegovukresearchmodelling-systems
history-of-numerical-weather-prediction) That same year
Norman Phillips completed a 2-layer hemispheric quasi-
geostrophic computer model that is generally regarded as
the first atmospheric general circulation model (AGCM
Phillips 1956)
The year 1955 also marked the birth of the first con-
tinued effort under the US Weather Bureau to focus
on the development of AGCMs (Smagorinsky 1983)
Smagorinskyrsquos laboratory initially located in Suitland
Maryland moved to Washington DC and in 1968
gelled at Princeton University as the Geophysical Fluid
Dynamics Laboratory (GFDL) Syukuro Manabe who
joined Smagorinskyrsquos group in 1959 was a pioneer in
model development (Manabe et al 1965) In a seminal
paper published in 1975 it was shown that the temper-
ature response to a doubling of atmospheric carbon di-
oxide would be magnified in high latitudes as a result of
the recession of the snow and sea ice boundaries and the
thermal stability of the lower troposphere that limits
vertical mixing (Manabe and Wetherald 1975)
By the mid-1960s climate model development was
being led by several groups in addition to GFDL the
University of California Los Angeles Department of
Meteorology the Lawrence Livermore Laboratory and
the National Center for Atmospheric Research By the
1970s this had expanded to include the RAND corpo-
ration the National Aeronautics and Space Adminis-
tration (NASA) Goddard Institute for Space Sciences
and the Australian Numerical Meteorological Research
Centre The Arctic was not a primary consideration in
CHAPTER 21 WAL SH ET AL 2115
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
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1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
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doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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Binder H M Boettcher C M Grams H Joos S Pfahl and
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The Physical Science Basis T F Stocker et al Eds Cam-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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Climatological aspects of cyclogenesis near Adelie Land
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G A Weidner and A B Wilson 2013 Central West Ant-
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Central West Antarctica among the most rapidly warming
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ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
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Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
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over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
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Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
the development of the atmospheric component ofmodels
although credible simulations of sea ice and snow cover
were recognized as important to realistic simulations of
the albedondashtemperature feedbacks
h The International Geophysical Year (thirdInternational Polar Year)
The IGY also referred to as the third IPY took place
from July 1957 through December 1958 The IGY was an
international effort to coordinate the collection of geo-
physical data from around the world including both polar
regions It marked the beginning of a new era of scientific
discovery at a time when many innovative technologies
were appearing While Greenland and the upper atmo-
sphere were emphases of Arctic activities the IGY was a
watershed event for the Antarctic A continentwide dis-
tribution of weather stations was established (Fig 21-9)
The IGY marks the start of sustained instrumental ob-
servations from Antarctica and thus the beginning of
many climatic records from this remote continent such
as are available from theMetREADERdatabase (https
legacybasacukmetREADERdatahtml) An interna-
tional analysis center was established at the LittleAmerica
V station to produce the first surface and upper-air
weather maps for Antarctica and the Southern Ocean
(Moreland 1958) that were broadcast once a day Several
of the participants (egH vanLoon andPDAstapenko)
subsequently made major advances in Antarctic meteo-
rology The launch of the first satellites during the IGY
presaged the start of the comprehensive satellite network
that today is a foundation for modern numerical weather
prediction in high southern latitudes A symposium on
Antarctic meteorology held in Melbourne in February
1959 highlighted the coming explosion of meteorological
FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the
station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-
lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]
2116 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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Climatological aspects of cyclogenesis near Adelie Land
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ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
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Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
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Candlish L M R L Raddatz G G Gunn M G Asplin and
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Carruthers J N 1941 Some interrelationships of meteorology
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
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mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
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Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
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Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
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Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
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1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
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Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
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McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
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mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
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2002 Measurements near the atmospheric surface group
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
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TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
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Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
knowledge stimulated by the IGY One contribution was
the seminal effort of Ball (1960) who formulated a simple
set of equations describing the first order behavior of the
Antarctic surface winds OnceAntarctic terrain elevations
were determined with sufficient accuracy this system of
equations was exploited by Parish andBromwich (1987) to
derive a realistic depiction of theAntarctic katabaticwinds
and their concentration into a small number of conflu-
ence zones such as the one that sustains the lsquolsquoHome of the
Blizzardrsquorsquo at Cape Denison
Prior to the IGY seven countries claimed parts of
Antarctica with some of the claims overlapping while
eight other countries made no assertions of sovereignty
the latter included the United States which did not rec-
ognize the seven claims but reserved the right to make its
own in the future (httpswwwstategovtavctrty193967
htm) To preserve the continent for cooperative scientific
study and peaceful purposes that characterized the IGY
the Antarctic Treaty was signed at the National Academy
of Sciences in Washington DC on 1 December 1959 by
the 12 nations whose scientists had been active in and
around Antarctica during the IGY The Antarctic Treaty
set aside the issue of territorial claims but did not in-
validate them The treaty came into force in 1961 It has
now been acceded to by 53 nations and governs interna-
tional activities south of 608S The Scientific Committee
on Antarctic Research (SCAR) that was established at
the same time provides scientific advice to the Antarctic
Treaty System and has for example been a leading pro-
ponent of the Year of Polar Prediction (Jung et al 2016)
that is under way at the time of writing (section 5k)
Several efforts resulting primarily from the IGY led
to notable advances in meteorological knowledge of the
Southern Ocean and Antarctica Harry van Loon Jan
J Taljaard and colleagues were leaders in laying out the
basic characteristics of the atmospheric circulation cul-
minating in the Meteorology of the Southern Hemisphere
(Newton 1972) monograph One topic emphasized by van
Loon was the elucidation explanation and consequences
of the semiannual oscillation in atmospheric pressure and
wind so prevalent over the circumpolar ocean surround-
ingAntarctica (eg vanLoon 1967) Rusin (1964) focused
on the radiation and surface energy budget of Antarctica
primarily using observations from Russian stations
Schwerdtfeger (1970) presented a synthesis of Antarctic
climate that included detailed surface climatic descrip-
tions for 25 stations many based on a decade of obser-
vations starting from the IGY
5 1970s to the present (the modernsatellite era)
In the period since 1970 progress in polar meteorology
has greatly accelerated largely as a result of advances in
computer modeling satellite remote sensing and auton-
omous instrumentation Below we highlight these ad-
vances together with several globally significant weather
and climate challenges inwhich these advances have been
essential for scientific understanding and in at least one
case (the Antarctic ozone hole) mitigation actions
a The Global Weather Experiment The First GARPGlobal Experiment
In the early 1970s the Global Weather Experiment
initially known as the First Global Atmospheric Re-
search Program (GARP) Global Experiment (FGGE)
led to major progress in numerical weather prediction
To paraphrase Hollingsworth (1989) the primary goals
of FGGE were to describe the global behavior of the
atmosphere for one full year to greatly enhance nu-
merical weather prediction on the global scale and to
design an optimal observing system for this purpose lsquolsquoIn
practice the goal of the observational programme was
to describe the dynamics and thermodynamics of the
atmosphere with a horizontal resolution of about 500 km
for the whole year and with as good a vertical resolution
as possible Themain focus of the experiment was on the
tropics and on the Southern Hemispherersquorsquo
The resources required for the experiment were sub-
stantial For the first time there was a global constella-
tion of meteorological satellites consisting of lsquolsquofive
geostationary spacecraft and two polar orbiters In ad-
dition extensive deployments of ships aircraft with
dropsonde capability high-level and low-level super-
pressure balloons and drifting buoys in remote ocean
areas (especially in the Southern Ocean) along with
greatly enhanced rawinsonde and synoptic station cov-
erage both in space and time were implementedrsquorsquo (from
Hollingsworth 1989 with edits) ECMWF was founded
in 1975 to exploit the anticipated advances in global
numerical weather prediction up to 10 days ahead fol-
lowing from the Global Weather Experiment
b Discovery and understanding of the Antarcticozone hole
The stratospheric Antarctic ozone hole was discovered
in the mid-1980s by scientists from the British Antarctic
Survey (Farman et al 1985) by using total ozone amounts
that were derived from ground-based Dobson spectro-
photometer measurements at Halley and Argentine Is-
lands stations that started in the IGY This severe ozone
depletion was subsequently confirmed to be an Antarctic-
wide phenomenon in the austral spring by instruments on
the Nimbus-7 satellite that had been operating since 1978
(Stolarski et al 1986) until the publication of the Farman
et al paper overly conservative processing of theNimbus-
7 ozone retrievals had hidden the ozone holersquos presence
CHAPTER 21 WAL SH ET AL 2117
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
REFERENCES
Abbe C 1892 Memoir of William Ferrel 1817ndash1891 Biograph-
ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
tion Reconstructions over the Earth (ACRE) Initiative Bull
Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
2011BAMS32181
Anderson R B Bolville and D E McClellan 1955 An opera-
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Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
ternational Polar Years (IPYs) From Pole to Pole Vol 1
Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
covery 1776ndash1880 Part 1 Journals of Captain James Cook on his
Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
Bedel B 1954 Les observations meacuteteacuteorologiques de la station
Franccedilaise du Groenland conditions atmospheacuteriques en alti-
tude (Meteorological observations of the French Greenland
station atmospheric conditions at altitude) Expeacuteditions Po-laires Franccedilaises Missions Paul-Emile Victor Resultats Sci-
entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
early twentieth-century warming in the ArcticmdashA possible
mechanism J Climate 17 4045ndash4057 httpsdoiorg1011751520-0442(2004)0174045TETWIT20CO2
Bent S 1872 Thermal Paths to the Pole An Address Delivered
before the St Louis Mercantile Library Association RP
Studley Co 40 pp
Bessels E 1876 Scientific results of the United States Arctic ex-
pedition Steamer Polaris CF Hall commanding US Navy
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orgdetailscu31924029881095pagen5
Binder H M Boettcher C M Grams H Joos S Pfahl and
H Wernli 2017 Exceptional air mass transport and dy-
namical drivers of an extreme wintertime Arctic warm
eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg
1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
bridge University Press 867ndash952
Bockstoce J R and D B Botkin 1983 The historical status and re-
duction of thewesternArctic bowheadwhale (Balaenamysticetus)
population by the pelagic whaling industry 1848ndash1914 In-
ternational Whaling Commission Rep SC32PS16 107ndash141 pp
httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
katabatic winds and the Terra Nova Bay polynya Polar Rec
21 137ndash146 httpsdoiorg101017S0032247400004514
mdashmdash and R L Fogt 2004 Strong trends in the skill of the ERA-40
and NCEPNCAR reanalyses in the high and middle latitudes
of the Southern Hemisphere 1958ndash2001 J Climate 17 4603ndash
4619 httpsdoiorg10117532411
mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner
1993 Spatial and temporal variations of the intense katabatic
winds at Terra Nova Bay Antarctica Antarctic Meteorology
and Climatology Studies Based on Automatic Weather Sta-
tions D H Bromwich and C R Stearns Eds Antarctic
Research Series Vol 61 Amer Geophys Union 47ndash68
mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
Hughes 2004 Polar MM5 simulations of the winter climate of the
Laurentide IceSheet at theLGM JClimate17 3415ndash3433 https
doiorg1011751520-0442(2004)0173415PMSOTW20CO2
mdashmdash KM Hines and L-S Bai 2009 Development and testing of
Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
httpsdoiorg1010292008JD010300
mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
since 1989 in contemporary global reanalyses J Climate 24
4189ndash4209 httpsdoiorg1011752011JCLI40741
mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
arctica among the most rapidly warming regions on Earth
Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash and mdashmdash 2014 Corrigendum
Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
changing climate Environ Res Lett 10 025003 httpsdoiorg
1010881748-9326102025003
2130 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Subsequently satellite measurements have provided com-
prehensive mapping of the Antarctic ozone hole and its
rate of change Figure 21-10 shows that ozone depletion
was modest in 1979 but extreme in the 2000s Direct
measurements of the stratospheric chemistry started in
1986 with the National Ozone Experiment (NOZE) at
McMurdo Station This led to the explanation that het-
erogeneous chemical reactions involving anthropogenic
chlorofluorocarbons (CFCs) and polar stratospheric clouds
release atomic chlorine gas that catalyzes the destruction of
ozone (eg Solomon et al 1986 Douglass et al 2014) In
1987 the international Protocol on Substances that De-
plete theOzone Layer was signed inMontreal to phase out
CFC emissions Direct confirmation that the reductions in
CFC emissions have led to the recovery of the Antarctic
ozone hole was reported by Strahan and Douglass (2018)
The Antarctic ozone hole has a major impact on the tro-
pospheric circulation by strengthening the circumpolar
westerly winds over the Southern Ocean (Thompson and
Solomon 2002) and moving them poleward The varying
strength of these circumpolar westerlies known as the
southern annular mode (SAM) represents the extra-
tropical Southern Hemispherersquos dominant mode of large-
scale atmospheric variability andhasmany climatic impacts
(eg Thompson et al 2011 Wang and Cai 2013)
c The International Arctic Buoy Programme
Amajor milestone for monitoring the weather and sea
ice in the Arctic Ocean was the establishment of a
network of automatic data buoys to provide synoptic-
scale fields of sea level pressure surface air temperature
and ice motion (Thorndike and Colony 1981) From a
recommendation of the National Academies of Sciences
the Arctic Ocean Buoy Program began its deployments
of buoys on the sea ice surface in early 1979 in support of
the Global Weather Experiment (section 5a) Coordi-
nated by the University of Washington Applied Physics
Laboratoryrsquos Polar Science Center the program in 1991
became known as the International Arctic Buoy Pro-
gramme (IABP httpiabpapluwedu) with funding
provided by US agencies and various other nations As
the buoy program approaches four decades of operation
its uses have included the real-time support of operations
ingestion into reanalyses and diagnostic studies encom-
passing the time scales of weather the seasonal cycle
interannual variability and climate change
The first buoys were sheltered instruments deployed
on the ice surface to measure atmospheric pressure air
temperature and position Interrogated by satellite at
frequent (approximately hourly) intervals the atmo-
spheric measurements have always been available in
nearndashreal time for ingestion intomodels used for weather
forecasts or reanalyses Changes in a buoyrsquos location over
time enable the calculation of ice velocity With 20ndash30
buoys operating over the Arctic Ocean during much of
the IABPrsquos first few decades (Fig 21-11) more-accurate
fields of sea level pressure and ice velocity were con-
structed Such fields dating back to 1979 at daily intervals
FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)
during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these
years contrasts with (top left) 1979 during which ozone concentrations were much higher
2118 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
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entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
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Bessels E 1876 Scientific results of the United States Arctic ex-
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Binder H M Boettcher C M Grams H Joos S Pfahl and
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Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bockstoce J R and D B Botkin 1983 The historical status and re-
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httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
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mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner
1993 Spatial and temporal variations of the intense katabatic
winds at Terra Nova Bay Antarctica Antarctic Meteorology
and Climatology Studies Based on Automatic Weather Sta-
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mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
Hughes 2004 Polar MM5 simulations of the winter climate of the
Laurentide IceSheet at theLGM JClimate17 3415ndash3433 https
doiorg1011751520-0442(2004)0173415PMSOTW20CO2
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Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
httpsdoiorg1010292008JD010300
mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
since 1989 in contemporary global reanalyses J Climate 24
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mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
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mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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1010881748-9326102025003
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
are available from the Polar Science Center (eg
Thorndike and Colony 1981)
In the past two decades measurement capabilities of
the buoys have been expanded to include subsurface
variables such as ice and ocean temperature and salinity
Some buoys include ice mass balance (IMB) measure-
ments and an ice-tethered profiler (ITP) system The
IMB buoys consist of a series of thermistors spaced
10 cm apart from just above the sea ice down 3ndash5 m into
the ocean and acoustic pingers to measure snow depth
on sea ice and ice thickness from below in addition to
the fundamental surface air pressure and temperature to
support the IABP The ITP buoys consist of a small
surface capsule that sits atop an ice floe and supports a
plastic-jacketed wire rope tether extending through the
ice and down into the ocean ending with a weight
(intended to keep the wire vertical) A cylindrical un-
derwater apparatus mounts on the tether and cycles ver-
tically along it carrying oceanographic sensors through
the water column Water-property data are telemetered
from the ITP to shore in nearndashreal time The IABP now
maintains more than 100 buoys of varying sophistication
over the Arctic Ocean Most are placed on sea ice but
some are placed in openwater Buoys have an average life
span of 18 months In the future IABP hopes to increase
the average life span to 3ndash4 years
The data collected are used for real-time operations
and research Real-time operations include collecting
data for meteorological predictions IABP buoys have
helped to predict the trajectory of storms off the coast of
Alaska that otherwise would have been difficult to de-
termine Data collected by IABP buoys are also impor-
tant for forecasting sea ice conditions which are crucial
for coastal Alaskans for those engaged in subsistence
fishing and those who work in the coastal commercial
industry Shipping traffic in the Arctic region has in-
creased in recent years with the retreat of sea ice A
combination of sea level pressure air temperature and
sea ice motion help forecasters to predict better the
movement of Arctic Ocean sea ice
IABP buoys are also used to validate satellite prod-
ucts and complement the capabilities of satellite remote
sensing The NationalWeather Service and the National
Snow and Ice Data Center use buoy data for weather
FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the
previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)
CHAPTER 21 WAL SH ET AL 2119
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
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doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
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Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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Binder H M Boettcher C M Grams H Joos S Pfahl and
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Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
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mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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1010881748-9326102025003
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
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temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
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Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
predictions and ice charting IABP data are also used for
atmospheric reanalysis studies To date more than 800
scientific papers have been written using data from the
IABP Much of the data collected supports efforts for
theWorld Climate Research Programme and theWorld
Weather Watch
Contributors to the US section of IABP include the
US Coast Guard the US Department of Energy
NASA the US Navy the National Science Foundation
(NSF) and researchers from academic institutions such
as the Woods Hole Institution the US Armyrsquos Cold
Regions Research and Engineering Laboratory and the
Polar Science Center Researchers from private and
public organizations from the United States as well as
France Norway China Canada Japan South Korea
India and Russia contribute to the IABP
d Antarctic automatic weather stations
Until 1980 direct surface and upper-air meteorolog-
ical observations were provided by nearly the same
network of staffed locations as established for the IGY
(Fig 21-9) Charles R Stearns from the University of
WisconsinndashMadison led the implementation of the
satellite-transmitting automatic weather station (AWS)
network (Lazzara et al 2012) Funded largely by the
NSF the AWS network in Antarctica now consists of
about 60 active sites maintained primarily by the Uni-
versity of Wisconsin The AWS units typically measure
pressure temperature winds and atmospheric moisture
at 2ndash3 m above the surface at intervals of a few minutes
but the variables observed continue to expand The
sensors now include acoustic depth gauges to measure
changes in the snow surface height Because the AWS
are deployed in remote and challenging locations with at
most annual maintenance visits data outages do occur
therefore data analysis requires care The AWS net-
work has expanded to more than 100 locations across
Antarctica (Fig 21-12) through sites provided by many
nations including Australia France the United King-
dom China Japan and Italy as well as the United
States Observations from AWS sites are critical input
for Antarctic numerical weather prediction global re-
analyses and innumerable weather and climate studies
e Arctic clouds
Arctic clouds and their radiative interactions have
emerged as a critical component of the climate research
agenda Clouds have a strong warming influence on the
surface during much of the year in the Arctic and a
cooling effect for a short period in the summer The
period of negative cloud radiative forcing ranges from a
few weeks in the central Arctic Ocean to several months
over the subarctic land areas (Curry et al 1993
Schweiger and Key 1994 Curry et al 1996) Much of the
early work on the radiative impacts of clouds over the
Arctic Ocean was based on the radiation measurements
and cloud observations from the Russian drifting ice
stations (Marshunova and Mishin 1994 Walsh and
Chapman 1998) Cloud radiative properties are strongly
dependent not only on their elevation as in lower lati-
tudes but also on the phase (liquid vs ice) of the cloud
particles (Shupe et al 2015)
Research on Arctic clouds accelerated during the
1990s and 2000s with several major field programs (see
the appendix) The Surface Heat Budget of the Arctic
(SHEBA) a yearlong field experiment centered on a
ship intentionally frozen into the Arctic pack ice during
1997ndash98 showed that supercooled liquid water droplets
are surprisingly frequent over the Arctic Ocean Recent
estimates have indicated that liquid water is present in
10ndash80 of Arctic clouds depending on the season
and location (Shupe et al 2011 Cesana et al 2012)
SHEBA was followed in the early 2000s by the De-
partment of Energyrsquos Atmospheric Radiation Mea-
surementNorth Slope of Alaska (ARMNSA) program
which included the deployment of a variety of in-
strumentation for measuring radiation and clouds on the
northern Alaskan coast at Barrow and more recently
Oliktok Point The ARM program targeted improve-
ments on model formulations of cloudradiative pro-
cesses as one of its key objectives Over the years since
2000 the ARM program has included a wide variety of
manned and remote-controlled airborne measurements
(McFarquhar et al 2011 Schmid et al 2016) including
the Mixed-Phase Arctic Cloud Experiment (M-PACE
Verlinde et al 2007) during whichArctic cloud particles
were sampled extensively Another notable field study
was the Arctic Summer Cloud Ocean Study (ASCOS)
which took place in 2008 and utilized the Swedish ice-
breakerOden (Tjernstrom et al 2014) ASCOS targeted
the physical and chemical processes responsible for the
formation of the low-level clouds that are pervasive over
the Arctic Ocean during summer ASCOS measure-
ments have been used to improve model simulations of
late-summer Arctic clouds (eg Hines and Bromwich
2017) Another Arctic field campaign the Indirect and
Semi-Direct Aerosol Campaign (ISDAC) focused on
the impact of aerosols on Arctic clouds (McFarquhar
et al 2011) From these various field programs it has
become apparent that atmospheric radiation is impacted
much more by clouds containing liquid water than by
ice-crystal clouds (Shupe and Intrieri 2004) While
clouds containing liquid are in nearndashradiative equilib-
riumwith the surface thin clouds composed primarily of
ice allow considerable surface-emitted longwave radia-
tion to escape to space (Stramler et al 2011)
2120 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
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doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
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Bengtsson L V A Semenov and O M Johannessen 2004 The
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Binder H M Boettcher C M Grams H Joos S Pfahl and
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Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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Hughes 2004 Polar MM5 simulations of the winter climate of the
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httpsdoiorg1010292008JD010300
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Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
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mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
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Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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1010881748-9326102025003
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
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temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
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Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Advances in remote sensing have also led to progress
in documenting Arctic cloud characteristics and their
radiative effects While surfacendashcloud contrast limita-
tions inherent in visible and infrared sensors hindered
early uses of satellite products in the Arctic lidar and
radar profilers on the CloudSat and CloudndashAerosol
Lidar and Infrared Pathfinder Satellite Observations
(CALIPSO) satellites have been used to obtain Arctic
cloud climatologies that differ in some ways from earlier
depictions For example Liu et al (2012) showed that
cloud frequencies derived from radar and lidar profilers
on CloudSat and CALIPSO have seasonal maxima and
minima in autumn and winter respectively Climatol-
ogies based on surface observations generally showed
maximum frequencies in summer (eg Vowinckel and
Orvig 1971) The lidar and radar profile results also
showed that about 25 of Arctic clouds are multilay-
ered CloudSat and CALIPSO products have also been
used to assess weather prediction models simulations
of clouds (Candlish et al 2013) and radiative fluxes
(Zygmuntowska et al 2012)
Despite the importance of Arctic clouds and their
composition models still have difficulty in producing the
correct Arctic cloud types (de Boer et al 2012) and for
that reason poorly represent Arctic surface energy
fluxes (Tjernstrom et al 2008 Pithan et al 2014) For
simulations of climate these deficiencies have serious
implications for surface temperatures and cryospheric
change (Persson 2012) As noted in section 6 the Arctic
surface energy budget and its relation to clouds remain
major challenges of polar meteorology and polar climate
science This realization has driven the upcoming Multi-
disciplinary Drifting Observatory for Studies of Arctic
Climate (MOSAiC) program an international Arctic drift
expedition planned for the marginal ice zone in 2019ndash20
(Shupe et al 2016 httpswwwmosaic-expeditionorg
FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)
[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http
amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]
CHAPTER 21 WAL SH ET AL 2121
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Abbe C 1892 Memoir of William Ferrel 1817ndash1891 Biograph-
ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
2011BAMS32181
Anderson R B Bolville and D E McClellan 1955 An opera-
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Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
Bedel B 1954 Les observations meacuteteacuteorologiques de la station
Franccedilaise du Groenland conditions atmospheacuteriques en alti-
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entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
early twentieth-century warming in the ArcticmdashA possible
mechanism J Climate 17 4045ndash4057 httpsdoiorg1011751520-0442(2004)0174045TETWIT20CO2
Bent S 1872 Thermal Paths to the Pole An Address Delivered
before the St Louis Mercantile Library Association RP
Studley Co 40 pp
Bessels E 1876 Scientific results of the United States Arctic ex-
pedition Steamer Polaris CF Hall commanding US Navy
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Binder H M Boettcher C M Grams H Joos S Pfahl and
H Wernli 2017 Exceptional air mass transport and dy-
namical drivers of an extreme wintertime Arctic warm
eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg
1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bockstoce J R and D B Botkin 1983 The historical status and re-
duction of thewesternArctic bowheadwhale (Balaenamysticetus)
population by the pelagic whaling industry 1848ndash1914 In-
ternational Whaling Commission Rep SC32PS16 107ndash141 pp
httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
katabatic winds and the Terra Nova Bay polynya Polar Rec
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and NCEPNCAR reanalyses in the high and middle latitudes
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mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner
1993 Spatial and temporal variations of the intense katabatic
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and Climatology Studies Based on Automatic Weather Sta-
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Research Series Vol 61 Amer Geophys Union 47ndash68
mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
Hughes 2004 Polar MM5 simulations of the winter climate of the
Laurentide IceSheet at theLGM JClimate17 3415ndash3433 https
doiorg1011751520-0442(2004)0173415PMSOTW20CO2
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Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
httpsdoiorg1010292008JD010300
mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
since 1989 in contemporary global reanalyses J Climate 24
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mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
arctica among the most rapidly warming regions on Earth
Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
M Wang US Bhatt and R L Thoman 2017 Surface air
temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
fileadminuser_uploadMOSAiCDocumentsMOSAiC_
Implementation_Plan_April2018pdf)
f Satellite-derived soundings of the atmosphere
Radiation emitted by Earthrsquos atmospheric gases and by
clouds is recorded by polar-orbiting satellites in the infrared
and microwave wavelengths These emissions can be used
to infer the temperature and moisture content of the broad
atmospheric layers from which they originate using emis-
sion weighting functions Profiles of atmospheric tempera-
ture and water vapor amounts from across the globe
are provided by spaceborne observations for numerical
weather prediction These profiles are especially valuable in
the polar regions where the network of rawinsonde stations
has large gaps over the polar oceans and even over land
The era of satellite sounding of the atmosphere pri-
marily started with the launch of the TIROS-N space-
craft in 1978 (httpssciencenasagovmissionstiros) for
the Global Weather Experiment It included the first
TIROS Operational Vertical Sounder (TOVS) that
consisted of the High Resolution Infrared Radiation
Sounder (HIRS) theMicrowave SoundingUnit (MSU)
and on some satellites the Stratospheric Sounding Unit
(SSU) Satellite sounding has advanced tremendously
since the 19 channel HIRS era A recent example is
the InfraredAtmospheric Sounder InterferometerndashNew
Generation (IASI-NG) sounder that has 16 920 channels
spanning the infrared from 362 to 1550 mm Designed
for temperature and humidity sounding ozone profiling
and total-column or profiles of greenhouse gases it is
planned for flight on the European MetOp series of
polar orbiters starting in the 2021 time frame (https
wwwwmo-satinfooscarinstrumentsview206)
g The fourth International Polar Year (2007ndash09)
According to Krupnik et al (2011)
the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations
Although meteorology was the major focus of the first
IPY (1882ndash83) the 2007ndash09 IPY was far broader in its
scientific projects and involved a large range of disciplines
spanning geophysics ecology human health social sci-
ences and the humanities This increased breadth in-
dicates that modern atmospheric science has become
multidisciplinary In many cases there was a significant
atmospheric component to IPY projects carried out in
topic areas such as ice ocean land people and others
(Krupnik et al 2011 p 137) Purely atmospheric topics
included the International Arctic Systems for Observing
the Atmosphere (IASOA) observing network radiation
measurements from Spitzbergen aerosol measurements
in the Arctic and Antarctic investigations of Antarctic
polar stratospheric clouds and associated ozone de-
pletion initiation of the regional synthesis of the physical
components of Arctic climate known as the Arctic Sys-
tem Reanalysis (section 5h) investigations of Arctic
weather phenomena and their forecastability as a prelude
to the Polar Prediction Project (section 5k) the Con-
cordiasi Project over Antarctica that featured develop-
ment of more effective assimilation of radiances from
hyperspectral infrared and microwave sounders over
snow and ice and also featured dropsondes launched re-
motely from stratospheric superpressure balloons in part
to improve numerical weather prediction and also as a
run-up to the Polar Prediction Project and investigations
of air pollutants impacting the Arctic
h Reanalyses and the polar regions
Global reanalyses provide valuable tools for investigating
climate variability and change in the data-sparse polar re-
gions for example exploring the spatial and temporal
variability of Antarctic snow accumulation (Medley et al
2013) These reanalysis datasets are produced by merging
a short-term numerical weather prediction with a wide
variety of ground-based aircraft and satellite-based ob-
servations of the atmosphere while taking into account
uncertainties in both the prediction and the observations
However there are some important issues in using rean-
alyses to investigate polar climate change Although the
data assimilation system and the forecast model do not
change artificial shiftstrends can arise because of the
changing observing system This sensitivity is heightened in
high southern latitudes because of limited direct meteoro-
logical observations prior to the Global Weather Experi-
ment in 1979 (eg Bromwich and Fogt 2004) For example
the introduction of satellite atmospheric sounding data in
late 1978 produced a jump in the Antarctic precipitation
minus evapotranspiration (P2 E) simulated by the ERA-
40 global reanalysis (eg van de Berg et al 2005) Even
during themodern satellite era (after 1978) the assimilation
of radiances from theAdvancedMicrowave SoundingUnit
(AMSU) in the late 1990s introduced a pronounced jump
into the precipitation forecast by the MERRA global re-
analysis (eg Bromwich et al 2011a)Global reanalyses are
2122 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
tion Reconstructions over the Earth (ACRE) Initiative Bull
Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
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Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
ternational Polar Years (IPYs) From Pole to Pole Vol 1
Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
covery 1776ndash1880 Part 1 Journals of Captain James Cook on his
Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
Bedel B 1954 Les observations meacuteteacuteorologiques de la station
Franccedilaise du Groenland conditions atmospheacuteriques en alti-
tude (Meteorological observations of the French Greenland
station atmospheric conditions at altitude) Expeacuteditions Po-laires Franccedilaises Missions Paul-Emile Victor Resultats Sci-
entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
early twentieth-century warming in the ArcticmdashA possible
mechanism J Climate 17 4045ndash4057 httpsdoiorg1011751520-0442(2004)0174045TETWIT20CO2
Bent S 1872 Thermal Paths to the Pole An Address Delivered
before the St Louis Mercantile Library Association RP
Studley Co 40 pp
Bessels E 1876 Scientific results of the United States Arctic ex-
pedition Steamer Polaris CF Hall commanding US Navy
Rep Government Printing Office 986 pp httpsarchive
orgdetailscu31924029881095pagen5
Binder H M Boettcher C M Grams H Joos S Pfahl and
H Wernli 2017 Exceptional air mass transport and dy-
namical drivers of an extreme wintertime Arctic warm
eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg
1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
bridge University Press 867ndash952
Bockstoce J R and D B Botkin 1983 The historical status and re-
duction of thewesternArctic bowheadwhale (Balaenamysticetus)
population by the pelagic whaling industry 1848ndash1914 In-
ternational Whaling Commission Rep SC32PS16 107ndash141 pp
httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
katabatic winds and the Terra Nova Bay polynya Polar Rec
21 137ndash146 httpsdoiorg101017S0032247400004514
mdashmdash and R L Fogt 2004 Strong trends in the skill of the ERA-40
and NCEPNCAR reanalyses in the high and middle latitudes
of the Southern Hemisphere 1958ndash2001 J Climate 17 4603ndash
4619 httpsdoiorg10117532411
mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner
1993 Spatial and temporal variations of the intense katabatic
winds at Terra Nova Bay Antarctica Antarctic Meteorology
and Climatology Studies Based on Automatic Weather Sta-
tions D H Bromwich and C R Stearns Eds Antarctic
Research Series Vol 61 Amer Geophys Union 47ndash68
mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
Hughes 2004 Polar MM5 simulations of the winter climate of the
Laurentide IceSheet at theLGM JClimate17 3415ndash3433 https
doiorg1011751520-0442(2004)0173415PMSOTW20CO2
mdashmdash KM Hines and L-S Bai 2009 Development and testing of
Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
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mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
since 1989 in contemporary global reanalyses J Climate 24
4189ndash4209 httpsdoiorg1011752011JCLI40741
mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
arctica among the most rapidly warming regions on Earth
Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash and mdashmdash 2014 Corrigendum
Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
changing climate Environ Res Lett 10 025003 httpsdoiorg
1010881748-9326102025003
2130 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
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Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
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mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
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around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
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(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
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mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
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Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
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orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
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Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
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Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
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BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
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2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
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of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
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Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
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101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
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mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
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Parish T R and D H Bromwich 1987 The surface windfield over
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mdashmdash and R Walker 2006 A re-examination of the winds of
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
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2002 Measurements near the atmospheric surface group
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
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Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
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Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
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TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
less problematic in high northern latitudes as a result of
extensive surface and upper-air observations collected from
the land areas surrounding the Arctic Ocean As for the
Antarctic the greatest challenges arise for those variables
that are not observed but depend on the model physics for
their generationmdashnamely clouds precipitation radiative
fluxes and surface energy fluxes (Lindsay et al 2014)
A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-
ward of 408N) has been produced for 2000ndash12 to
provide a more refined tool to investigate rapid climate
change happening inArctic latitudes Two versions of the
Arctic System Reanalysis (ASR) are available at 30-km
(version 1) and 15-km (version 2) grid spacing with a high
vertical resolution (eg Bromwich et al 2018) and the
latter is being updated to the present The strengths of
this high-resolution regional reanalysis reside in its more
accurate reproduction of surface variable behavior (10-m
wind 2-m air temperature etc) and in realistically cap-
turing topographically forced winds The ASR also pro-
vides an improved depiction of cyclones relative to
coarser global reanalyses including polar lows (Smirnova
and Golubkin 2017) although approximately one-third
of the polar lows are not analyzed by the ASR For such
purposes the effective resolution of the ASR is about 7
times the 15-km resolution (Skamarock 2004)
i Arctic amplification and the recent Arctic warming
Arctic amplification which refers to the observation that
the Arctic warms and cools faster than the rest of the
Northern Hemisphere and the global mean has become a
major topic of climate research Figure 21-7 illustrates this
behavior by showing the annual values of the Arctic and
global temperatures since 1900 In recent decades the
Arctic has warmed at twice the rate of the global and
Northern Hemispheric mean temperatures Arctic ampli-
fication a long-expected Arctic response to climate warm-
ing and evident in simulations from even the earliest
generation of global climate models (eg Manabe and
Wetherald 1975) started to clearly emerge toward the end
of the twentieth century (Serreze et al 2009 Screen and
Simmonds 2010) One of the major drivers of observed
Arctic amplification is sea ice loss open water areas de-
velop earlier in spring allowing for more absorption and
storage of solar energy in the oceanmixed layer through the
summer As the sun sets in autumn and winter this stored
heat is released upward to the atmosphere This heat loss
mechanism helps to explain why the Arctic amplification
signal tends to be stronger in autumn than in summer
However it is increasingly recognized that Arctic
amplification has other causes in addition to sea ice loss
Alexeev et al (2005) for example showed that polar
amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo
(ie systemswith no sea ice or snowcover) The complexity
of the processes and feedbacks challenges observational
assessments (and indeed has motivated special field pro-
grams such as SHEBA described in the appendix and
MOSAiC) For this reason comparative evaluations of
key feedbacks involved in Arctic amplification have re-
lied largely on global climate models (eg Taylor et al
2013 Pithan and Mauritsen 2014) In the latter study the
largest contributions to Arctic amplification were found
to arise from 1) the surface albedo (snow and ice) feed-
back and 2) the different vertical structure of thewarming
in high and low latitudes (lapse-rate effect) The next
largest contribution to Arctic amplification in the climate
models is the Planck effect which arises because theArctic
is colder at the top of the atmosphere than the subtropics
and radiates less energy to space While the water vapor
feedback is positive in theArctic it actually opposesArctic
amplification in climate models (Pithan and Mauritsen
2014 their Fig 2) If relative humidity stays nearly constant
in climate models then the ClausiusndashClapeyron equation
dictates a larger increase of water vapor in the tropics than
in the polar regions thereby countering polar amplifica-
tion The net role of clouds in the models was found small
but can be large in a particular season of a particular
year The largest and only substantial negative feedback in
the models is ocean heat transport which decreases as
the Arctic warms thereby reducing the Arctic warming
The different contributions vary among the global climate
models and the range of uncertainty is especially large in
the ocean transport feedback The feedbacks associated
with clouds and atmospheric transport also have wide
ranges
Atmospheric transport has also been a key contribu-
tor to recent extreme warming events For example
during January 2016 the Arctic-wide averaged tem-
perature anomaly was 208C above the previous record
of 308C (Fig 21-13a Overland and Wang 2016 Kim
et al 2017) This event caught the publicrsquos attention with
reports of temperatures warming to near the freezing
point at the North Pole The event was caused by ad-
vection of heat and moisture into the Arctic on Atlantic
and Pacific pathways as shown by contour directions
of the 700-hPa geopotential height field for January
February 2016 (Fig 21-13b) Northward advection of
temperature and moisture also results in an increase
of downward longwave radiation further warming the
surface and reducing sea ice buildup (Cullather et al
2016 Binder et al 2017 Rinke et al 2017) A similar
event occurred in the winter 201718 (Overland and
Wang 2018) Consistent with the recent Arctic warming
and the temperaturendashalbedo feedback the Arctic has
experienced record low sea ice during multiple winters
(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea
ice has shifted from mostly multiyear thick (3 m) to
CHAPTER 21 WAL SH ET AL 2123
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Cohen J and Coauthors 2014 Recent Arctic amplification and
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Crawford A and M C Serreze 2015 A new look at the Arctic
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JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
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semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
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Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
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Overview of Arctic cloud and radiation characteris-
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Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
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ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
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de Boer G W Chapman J Kay B Medeiros M D Shupe
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Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
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Dorsey H G Jr 1945 Some meteorological aspects of the
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Douglass A P Newman and S Solomon 2014 The Antarctic
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DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
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R Osinski and A Roberts 2016 Winter atmospheric buoy-
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around southeasternGreenland in theRegionalArctic System
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Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
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English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
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Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
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315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
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regions Proc Amer Philos Soc 49 57ndash129
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Circulation MacMillan 198 pp
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143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
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mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
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Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
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McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
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Page J 1900 Ice and ice movements in Bering Sea during the
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Palmeacuten E 1951 The role of atmospheric disturbances in the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
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Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
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Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
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Rodionov S N J E Overland and N A Bond 2005 The
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Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
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Screen J A and I Simmonds 2010 The central role of diminishing
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spheric response to Arctic sea-ice loss across climate modelsNat
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
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Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
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mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
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Taylor P C M Cai A Hu J Meehl W Washington and G J
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Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Thomson A 1948 The growth of meteorological knowledge of
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ThorndikeA S andRColony 1981ArcticOceanBuoy Program
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Timmermans M L J Toole and R Krishfield 2018Warming of the
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Centre sea ice and sea surface temperature data set version 2
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
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mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
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Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
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JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
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Untersteiner N A S Thorndike D A Rothrock and K L
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CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
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1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
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van Loon H 1967 The half-yearly oscillations in middle and high
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THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
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circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
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Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
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von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
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mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
mostly thin (1 m) sea ice that formed in the previous
winter (Meier et al 2014) BothArctic temperatures and
sea ice conditions are now well beyond previous expe-
rience from the twentieth century
j Regional modeling of the polar regions
1) THE ANTARCTIC MESOSCALE PREDICTION
SYSTEM
The need for optimized numerical weather prediction
for Antarctica became apparent in 1999 when Dr Jerri
Nielsen was stranded at AmundsenndashScott South Pole
Station with a serious medical condition The key ques-
tion was When would the temperature warm up enough
for planes to land safely to evacuate her in the austral
spring No convincing forecast capability existed to
provide this information As a result the Antarctic Me-
soscale Prediction System (AMPS) started in 2000 as a
collaboration between the National Center for Atmo-
spheric Research (NCAR) and the Byrd Polar Research
Center of The Ohio State University to provide an opti-
mized forecasting capability for the US Antarctic Pro-
gram (Powers et al 2012) It featuredmuch higher spatial
resolution than existing global models physical parame-
terizations optimized for the Antarctic environment and
regional data assimilation The current configuration of
nested grids is shown in Fig 21-15 with the finest reso-
lution of 09 km around Ross Island where the extensive
US aircraft operations are focused near McMurdo Sta-
tion and an 8-km grid covering all of Antarctica Every
AMPS forecast is archived at NCAR Exploration of the
early parts of the forecast that are most accurate (after
12 h of spinup from a cold start) has led to substantial
advances in understanding of Antarctic atmospheric
processes including the surface winds (eg Nigro and
Cassano 2014) storm-generation mechanisms in the
most active cyclogenesis region in the Southern Hemi-
sphere (Bromwich et al 2011b) Antarctic precipitation
(Schlosser et al 2016) and the climate of West Antarc-
tica (Nicolas and Bromwich 2011)
2) REGIONAL CLIMATE MODELING
During the last two decades there have been substantial
efforts devoted to regional atmospheric modeling of both
polar regions The polar version of the Fifth-generation
Pennsylvania State UniversityndashNational Center for At-
mospheric Research Mesoscale Model (Polar MM5 eg
Cassano et al 2001) and its successor the polar version of
the Weather Research and Forecasting (WRF) Model
(Polar WRF eg Bromwich et al 2009) were developed
to better characterize the high-latitude environments such
as sea ice areas extensive ice sheets and tundra regions
These models have been applied to a wide variety of
weather and climate problems such a simulating the cli-
mate of the Laurentide Ice Sheet during the last glacial
period (Bromwich et al 2004) Antarctic numerical
weather prediction via AMPS [section 5j(1)] the surface
winds near Greenland (eg DuVivier and Cassano 2013)
and conditions causing summer melting of ice shelves in
the Amundsen Sea embayment of West Antarctica (Deb
et al 2018) Other major efforts have involved the Re-
gional Atmospheric Climate Model (RACMO eg Noeumll
FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged
geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The
data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]
2124 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
tion Reconstructions over the Earth (ACRE) Initiative Bull
Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
ternational Polar Years (IPYs) From Pole to Pole Vol 1
Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
covery 1776ndash1880 Part 1 Journals of Captain James Cook on his
Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
Bedel B 1954 Les observations meacuteteacuteorologiques de la station
Franccedilaise du Groenland conditions atmospheacuteriques en alti-
tude (Meteorological observations of the French Greenland
station atmospheric conditions at altitude) Expeacuteditions Po-laires Franccedilaises Missions Paul-Emile Victor Resultats Sci-
entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
early twentieth-century warming in the ArcticmdashA possible
mechanism J Climate 17 4045ndash4057 httpsdoiorg1011751520-0442(2004)0174045TETWIT20CO2
Bent S 1872 Thermal Paths to the Pole An Address Delivered
before the St Louis Mercantile Library Association RP
Studley Co 40 pp
Bessels E 1876 Scientific results of the United States Arctic ex-
pedition Steamer Polaris CF Hall commanding US Navy
Rep Government Printing Office 986 pp httpsarchive
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Binder H M Boettcher C M Grams H Joos S Pfahl and
H Wernli 2017 Exceptional air mass transport and dy-
namical drivers of an extreme wintertime Arctic warm
eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg
1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
bridge University Press 867ndash952
Bockstoce J R and D B Botkin 1983 The historical status and re-
duction of thewesternArctic bowheadwhale (Balaenamysticetus)
population by the pelagic whaling industry 1848ndash1914 In-
ternational Whaling Commission Rep SC32PS16 107ndash141 pp
httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
katabatic winds and the Terra Nova Bay polynya Polar Rec
21 137ndash146 httpsdoiorg101017S0032247400004514
mdashmdash and R L Fogt 2004 Strong trends in the skill of the ERA-40
and NCEPNCAR reanalyses in the high and middle latitudes
of the Southern Hemisphere 1958ndash2001 J Climate 17 4603ndash
4619 httpsdoiorg10117532411
mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner
1993 Spatial and temporal variations of the intense katabatic
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and Climatology Studies Based on Automatic Weather Sta-
tions D H Bromwich and C R Stearns Eds Antarctic
Research Series Vol 61 Amer Geophys Union 47ndash68
mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
Hughes 2004 Polar MM5 simulations of the winter climate of the
Laurentide IceSheet at theLGM JClimate17 3415ndash3433 https
doiorg1011751520-0442(2004)0173415PMSOTW20CO2
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Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
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mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
since 1989 in contemporary global reanalyses J Climate 24
4189ndash4209 httpsdoiorg1011752011JCLI40741
mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
arctica among the most rapidly warming regions on Earth
Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash and mdashmdash 2014 Corrigendum
Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
changing climate Environ Res Lett 10 025003 httpsdoiorg
1010881748-9326102025003
2130 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
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mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
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Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
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(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
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Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
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orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
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The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
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Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
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Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
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BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
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Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
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2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
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of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
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Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
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101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
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mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
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Parish T R and D H Bromwich 1987 The surface windfield over
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mdashmdash and R Walker 2006 A re-examination of the winds of
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
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2002 Measurements near the atmospheric surface group
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in
particular on the mass balance of the Greenland and
Antarctic ice sheets and their contribution to sea level rise
(eg Vernon et al 2013) The Regional Arctic System
Model (RASM Cassano et al 2017) is starting to be used
to explore atmospherendashoceanndashland coupled problems in
high northern latitudes (eg DuVivier et al 2016) RASM
includes a regional ocean model that can be run at reso-
lutions of several kilometers Another regional ocean-ice
model the Pan-Arctic Ice Ocean Modeling and Assimi-
lation System (PIOMAS) has been used to simulate the
evolution of the Arctic sea ice cover including an Arctic
sea ice volume reanalysis (Schweiger et al 2011) that is
updated in nearndashreal time The global NCARCommunity
Earth System Model has been applied with a wide range
of bipolar climate change problems such as the impact
of Arctic sea ice losses on the (northern) midlatitude
atmospheric circulation (Vavrus et al 2017) and the global
climatic impacts of Arctic sea loss (Tomas et al 2016)
k Polar Prediction Project and the Year of PolarPrediction 2017ndash19
The Polar Prediction Project (PPP httpwww
polarpredictionnet) is a 10-yr initiative (2013ndash22) of
the World Weather Research Programme of the World
Meteorological Organization (Jung et al 2016) The
mission of PPP is to lsquolsquopromote cooperative international
research enabling development of improved weather and
environmental prediction services for the polar regions
(Arctic and Antarctic) on time scales from hours to sea-
sonalrsquorsquo Its core activity is the Year of Polar Prediction
(YOPP) that will take place from mid-2017 to mid-2019
YOPP focuses on improving the polar observing system
facilitating field programs implementing better represen-
tation of key polar processes in coupled and uncoupled
FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006
average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen
Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-
ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]
CHAPTER 21 WAL SH ET AL 2125
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
mdashmdash 1893 The meteorological work of the U S Signal Service
1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
fication of surface warming on an aquaplanet in lsquolsquoghost forc-
ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
S Broumlnniman 2011 The International Atmospheric Circula-
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Soc 81 588ndash599 httpsdoiorg101002qj49708135008
Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
1959 Pergamon 9ndash16
Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue
mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
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entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
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Bent S 1872 Thermal Paths to the Pole An Address Delivered
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Binder H M Boettcher C M Grams H Joos S Pfahl and
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1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bockstoce J R and D B Botkin 1983 The historical status and re-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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and NCEPNCAR reanalyses in the high and middle latitudes
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1993 Spatial and temporal variations of the intense katabatic
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mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
Hughes 2004 Polar MM5 simulations of the winter climate of the
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doiorg1011751520-0442(2004)0173415PMSOTW20CO2
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mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
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mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
changing climate Environ Res Lett 10 025003 httpsdoiorg
1010881748-9326102025003
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
S156 httpsdoiorg1011752014BAMSStateoftheClimate1
Newton C W Ed 1972 Meteorology of the Southern Hemi-
sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp
Nicolas J P and D H Bromwich 2011 Climate of West Ant-
arctica and influence of marine air intrusions J Climate 24
49ndash67 httpsdoiorg1011752010JCLI35221
Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
organizing maps Mon Wea Rev 142 2361ndash2378 https
doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
R S W van de Wal and M R van den Broeke 2015 Evalu-
ation of the updated regional climate model RACMO23
Summer snowfall impact on the Greenland Ice Sheet Cryo-
sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015
Overland J E and M Wang 2016 Recent extreme Arctic tem-
peratures are due to a split polar vortex J Climate 29 5609ndash
5616 httpsdoiorg101175JCLI-D-16-03201
mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh
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temperature NOAA Arctic Report Card 2017 httpswww
arcticnoaagovReport-CardReport-Card-2017ArtMID
7798ArticleID700Surface-Air-Temperature
Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
general circulation Quart J Roy Meteor Soc 77 337ndash354
httpsdoiorg101002qj49707733302
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
101002qj3123
Parish T R and D H Bromwich 1987 The surface windfield over
the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg
101038328051a0
mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
httpsdoiorg101002grl50349
Penner C M 1955 A three-front model for synoptic analyses
Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002
qj49708134710
Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
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budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
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layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
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physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
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Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
models enhancing assimilation of polar observations
into models analyzing the predictability of sea ice on
various time scales evaluating the linkages between the
polar regions and midlatitudes developing forecast
verification approaches optimized for the polar regions
and exploring the linkage between the providers and
users of polar weather and ice information YOPP fea-
tures four special observing periods of enhanced obser-
vations and modeling namely FebruaryndashMarch 2018 in
the Arctic JulyndashSeptember 2018 in the Arctic mid-
November 2018ndashmid-February 2019 in the Antarctic
and FebruaryndashMarch 2020 in the Arctic to overlap with
MOSAiC drift across the Arctic Ocean (see section 6)
YOPP participants include the academic community and
operational forecast centers (including ECMWF and
NCEP) greatly enhancing the likelihood that YOPP
forecast improvements will be implemented to advance
regional and global numerical weather prediction for
both polar regions
6 Prioritiesopportunities for the next decade
It is apparent from the preceding review that there have
been tremendous advances in polar meteorology over the
past 100 years The study of polar weather and climate has
benefitted from advances in technology as well as a rap-
idly increasing cadre of scientists The recent warming of
the Arctic and the diminished coverage of sea ice and
snow have brought prominence to theArctic as a sentinel
of global change and the Antarcticrsquos ozone hole and its
anticipated recovery continue to make the Antarctic a
focus of monitoring and research
FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is
24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the
South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A
27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of
NCAR)
2126 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
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Compo G P and Coauthors 2011 The Twentieth Century Re-
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Crawford A and M C Serreze 2015 A new look at the Arctic
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JCLI-D-14-004471
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JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
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Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
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Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
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ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
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doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
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De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
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Dorsey H G Jr 1945 Some meteorological aspects of the
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1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
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DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
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R Osinski and A Roberts 2016 Winter atmospheric buoy-
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around southeasternGreenland in theRegionalArctic System
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Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
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Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
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315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
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in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
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1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Summer snowfall impact on the Greenland Ice Sheet Cryo-
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
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Page J 1900 Ice and ice movements in Bering Sea during the
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Palmeacuten E 1951 The role of atmospheric disturbances in the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
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by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
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Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
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Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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Rusin N P 1964 Meteorological and Radiational Regime of
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Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
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Screen J A and I Simmonds 2010 The central role of diminishing
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
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Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
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Taylor P C M Cai A Hu J Meehl W Washington and G J
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Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Thomson A 1948 The growth of meteorological knowledge of
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ThorndikeA S andRColony 1981ArcticOceanBuoy Program
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Timmermans M L J Toole and R Krishfield 2018Warming of the
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Centre sea ice and sea surface temperature data set version 2
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
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mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
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Tomas R A C Deser and L Sun 2016 The role of ocean heat
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JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
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Untersteiner N A S Thorndike D A Rothrock and K L
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CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
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1011751520-0477(2002)0830255SHBOTA23CO2
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van Loon H 1967 The half-yearly oscillations in middle and high
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THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
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circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
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Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
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balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
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von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
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Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
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mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
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for depicting Arctic sea ice variations back to 1850Geogr Rev
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Wang G and W Cai 2013 Climate-change impact on the 20th-
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Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
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Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
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schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Among the priorities that have emerged in polar
meteorology and climate research are the linkages
between polar and midlatitude weather and climate
Relationships between Arctic warming and extreme
weather and climate events in midlatitudes have been
suggested (Francis and Vavrus 2012 Cohen et al 2014)
but the robustness of the linkages has been questioned
and the mechanisms are unclear (Barnes and Screen
2015 Screen et al 2018) YOPP (section 5k) is an effort
to advance understanding and operational forecasting
capabilities in this regard Systematic assessments of the
impacts of polar data on forecasts in both hemispheres
can contribute to a firmer understanding of the impacts
of the polar regions on midlatitude weather and climate
Extreme events in the polar regions represent another
emerging research topic While changes in extreme
weather events in midlatitudes have been documented
especially increases of heavy precipitation events and
high-temperature occurrences comprehensive assess-
ments of changing extremes in the polar regions are
lacking Of particular interest in this regard are extreme
high-temperature events (Fig 21-7) which are favorable
for high-impact rain-on-snow events Other high-impact
events such as Arctic cyclones and their dynamical
precursors tropopause polar vortices (eg Hakim and
Canavan 2005 Cavallo and Hakim 2010) are poorly
documented and inconsistently simulated by weather
and climate models Moreover short-term sea ice vari-
ability has been linked toArctic cyclones (Simmonds and
Keay 2009 Simmonds and Rudeva 2012 Zhang et al
2013 Parkinson and Comiso 2013 Kriegsmann and
Bruumlmmer 2014) although the jury is still out on whether
Arctic cyclone activity will increase in the future On the
one hand increases in cyclone frequency andor intensity
will be favored by larger landndashsea temperature contrasts
in high latitudes during summer (Day and Hodges 2018)
on the other hand polar amplification will reduce the
overall northndashsouth baroclinicity of the midlatitudes
which are the source regions for many cyclones reaching
the Arctic during the nonsummer months
The surface energy budget of the Arcticmdashin particular
the role of polar clouds and radiationmdashcontinues to
challenge weather and climate prediction models Biases
in the surface radiative fluxes in global models are larger
than changes in those fluxes associated with changes in
sea ice cover Clouds and their radiative properties un-
doubtedly contribute to these biases Model tuning is
complicated by the ongoing transition from a multiyear
sea ice cover to a seasonal sea ice cover over the central
Arctic Ocean The upcoming MOSAiC program (Shupe
et al 2016) offers promise as a coordinated effort to im-
prove understanding and model simulation capabilities
with regard to the drivers of the surface energy budget
Finally work remains to be done in assessing and an-
ticipating the role of internal variability in polar climate
andweatherAs discussed in section 3b internal variability
has been at least partially responsible for multidecadal
temperature variations in the Arctic and most likely the
Antarctic as well The magnitude of internal variations
exceeds the changes arising from external forcing over
decadal time scales (Hodson et al 2013) anticipation of
changes over the yearly to decadal time scales relevant to
planners and decision-makers will have to contend with
this issue This challenge extends to the anticipation of
changes not only in atmospheric variables such as tem-
perature but in associated system components such as sea
ice snow cover and terrestrial surface variables
Acknowledgments The authors thank three anony-
mous reviewers for their constructive comments which
resulted in substantial improvements to the original
manuscript
APPENDIX
Significant Field Programs
a AIDJEX (1970ndash78)
The Arctic Ice Dynamics Joint Experiment (AIDJEX)
was the first major western sea ice experiment con-
structed specifically to answer emerging questions about
how sea ice moves and changes in response to the in-
fluence of the ocean and atmosphere In this respect it
was a scientific sequel to the voyages of the Jeannete and
the Fram as well as the drifting NP ice camps of the
Soviet Union AIDJEXwas also the first major scientific
effort conducted in the Arctic by US agencies [NSF
the National Oceanic and Atmospheric Administration
(NOAA) and the Office of Naval Research] since the
IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies
in 1971 and 1972 were followed by the main AIDJEX
field program from March 1975 to May 1976 The main
experiment consisted of a central camp surrounded
by three satellite camps arranged in a 150-km triangle
Surrounding these staffed camps was a polygon of eight
buoys at a distance of about 300 km from themain camp
AIDJEX was timely in that a new generation of ob-
serving technology was coming on line including satel-
lite navigation battery-powered buoys capable of
real-time transmission of position and other data via
satellite accurate temperaturendashsalinity probes for the
ocean in place of Nansen bottles quartz-oscillator ba-
rometers and laser equipment to measure ice defor-
mation over scales of several kilometers to several tens
of kilometers (Untersteiner et al 2009) That climate
CHAPTER 21 WAL SH ET AL 2127
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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doiorg101175MWR-D-11-001821
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Ubiquitous low-level liquid-containing Arctic clouds New obser-
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2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
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Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
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doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
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semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
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Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
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1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
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Sea and the adjacent waters US Coast and Geodetic Survey
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cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
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fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
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De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
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English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
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Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
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(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
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Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
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Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
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101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
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McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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North America Polar Sci 16 1ndash9 httpsdoiorg101016
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Page J 1900 Ice and ice movements in Bering Sea during the
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Palmeacuten E 1951 The role of atmospheric disturbances in the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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CHAPTER 21 WAL SH ET AL 2133
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
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Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
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cause climate model biases in Arctic wintertime temperature
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s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
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Screen J A and I Simmonds 2010 The central role of diminishing
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mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
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2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
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1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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the depletion of Antarctic ozoneNature 321 755ndash758 https
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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Strahan S E and A R Douglass 2018 Decline in Antarctic
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from Aura Microwave Limb Sounder observations Geophys
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
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Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
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Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
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doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Thomson A 1948 The growth of meteorological knowledge of
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arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
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Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
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2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
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Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
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Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
models were in need of more-realistic ice dynamics
formulations added to the timeliness of AIDJEX
One unexpected result from AIDJEX was the dis-
covery that mesoscale eddies are widespread in the up-
per layers of theArctic Ocean These eddies which were
shown to be baroclinic in nature have diameters of 10ndash
20 km and are found in in the uppermost 50ndash300m of the
water column Current speeds in their high-speed cores
are as large as 50ndash60 cm s21 about 5 times that of the
surrounding water A total of 146 eddies were crossed by
the AIDJEX station array during the 14-month main
observation period
The successful use of automatic data buoys to de-
termine air stress and ice deformation paved the way for
expanded uses of buoys in the Arctic Ocean AIDJEX
led directly to establishment of the Arctic Buoy Pro-
gram in 1978 followed by the extension to the IABP in
1991 (see section 5c) Another legacy of AIDJEX
stemming from the use of sequential Landsat imagery
from themain observing period ofAIDJEX is the use of
satellite data for ice kinematic information including
deformation rates and changes in leads and ridges
Synthetic aperture radar data from satellites are now
routinely processed into kinematic sea ice data for
testing modeled ice motion and for assimilation into
model hindcasts AIDJEX model development has a
dual legacy in the state-of-the-art sea ice models in-
cluding those used in Earth system models the ice
thickness distribution and a plastic failure criterion
Both these features of sea ice models were foci of the
AIDJEX measurement program
b SHEBA (1997ndash98)
The Surface Heat Budget of the Arctic funded by
NSF and the Office of Naval Research was a field
project designed to quantify energy transfer processes
that occur between the Arctic Ocean and the overlying
atmosphere Planning for SHEBA started with a series
of workshops held in the early 1990s SHEBAwas based
on the premise that addressing climate feedbacks and
improving the ability tomodel theArctic system required
improved understanding of the surface energy budget
and atmospherendashoceanndashice interactions SHEBA was in
part driven by emerging observations that the Arctic was
in the midst of rapid change (Uttal et al 2002) Phase I of
SHEBA involved analysis of historical data preliminary
modeling studies and development of instrumentation to
be used in the field program Phase II of SHEBAmdashthe
field elementmdashgot under way on 2 October 1997 when
the Canadian Coast Guard icebreaker Des Groseilliers
came to a halt in the Beaufort Sea and was allowed to be
frozen in Thus began a yearlong drift that lasted until
11 October 1998 At any given time there were 20ndash50
researchers at Ice Station SHEBA SHEBA collected a
complete annual cycle of observations over spatial scales
from meters to tens of kilometers of albedo snow
properties melt ponds ice growth and melt radiation
fluxes turbulent heat fluxes cloud height thickness and
other properties and ocean salinity temperature and
currents Persson et al (2002) describe the atmospheric
measurements made during the SHEBA field program
SHEBA data are still being widely used today Scientific
legacies of SHEBA include the realization that super-
cooled clouds are surprisingly frequent over the Arctic
Ocean (section 5e) the recognition of the importance of
Arctic cloud microphysical parameterizations in climate
model simulations and the discovery that an elevated
temperature inversion is often associated with Arctic
clouds (Pithan et al 2014) The latter complements the
earlier discovery that surface-based temperature in-
versions are widespread in the Arctic (section 2)
c CHAMP (early 2000s)
The Community-wide Hydrologic Analysis and
Monitoring Program (CHAMP) was a program to study
Arctic hydrology and its role in global change CHAMP
had its origins in a September 2000 workshop supported
by NSF to assess the existing state-of-the-art in Arctic
systems hydrology and to identify research priorities that
could lead to improved predictive understanding of feed-
backs arising from changes to the Arctic water cycle
CHAMP was organized around three interacting compo-
nents 1) compilation of data to better enable monitoring
and historical analysis of elements of the hydrologic sys-
tem 2) field observations and focused process studies and
3) the development of models operating over multiple
temporal and spatial scales CHAMP [ultimately funded
as the Freshwater Integration (FWI)] proved to be highly
successful effort The hydrologic cycle was shown to be
intimately connected to all major processes defining the
character of the Arctic system as a whole CHAMP
therefore provided a platform for collaboration between
scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)
Among the many accomplishments of CHAMP was a
much better understanding of the stocks and fluxes that
constitute of Arctic hydrologic cycle the freshwater bud-
get of the Arctic Ocean processes leading to variability
and change in river discharge and nutrient transports
d BOREAS (1990sndash2000s)
The Boreal EcosystemndashAtmosphere Study (BOREAS)
was a large-scale international interdisciplinary experi-
ment in the boreal forests of central Canada While most
large field programs from the 1970s through the 1990s
addressed interactions of the atmosphere with sea ice and
the ocean BOREAS focused on the exchanges of
2128 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Allan R P Brohan G Compo R Stone J Luterbacher and
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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Barnes E A and J A Screen 2015 The impact of Arctic
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Barr S and C Luumldecke Eds 2010 The History of the In-
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Bindoff N L and Coauthors 2013 Detection and attribution of
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The Physical Science Basis T F Stocker et al Eds Cam-
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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doiorg1011751520-0442(2004)0173415PMSOTW20CO2
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precipitation changes over Antarctica and the Southern Ocean
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Climatological aspects of cyclogenesis near Adelie Land
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mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
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Brooks C E P 1938 The warming Arctic Meteor Mag 73
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Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
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Candlish L M R L Raddatz G G Gunn M G Asplin and
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Carruthers J N 1941 Some interrelationships of meteorology
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
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mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
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doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
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1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
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101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
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English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
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Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
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(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
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Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
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Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
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McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
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Page J 1900 Ice and ice movements in Bering Sea during the
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Palmeacuten E 1951 The role of atmospheric disturbances in the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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CHAPTER 21 WAL SH ET AL 2133
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
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mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
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s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
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Screen J A and I Simmonds 2010 The central role of diminishing
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mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
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mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
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Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
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1913 Meteorology Thacker Spink amp Company 355 pp
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1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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measurements of the springtime Antarctic ozone decrease
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Strahan S E and A R Douglass 2018 Decline in Antarctic
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from Aura Microwave Limb Sounder observations Geophys
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
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Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
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Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
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doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Southern Hemisphere surface climate change Nat Geosci 4
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Thomson A 1948 The growth of meteorological knowledge of
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arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
radiative energy sensible heat water carbon dioxide and
other trace gases between the boreal forest and the lower
atmosphere Key questions targeted by BOREAS in-
cluded the following What processes control the ex-
changes of gases and energy between the boreal forest and
the atmosphere How will climate change affect the for-
est How will changes in the forest affect weather and
climate The most intensive field experiments took place
in the mid-1990s although additional measurements
analysis and applications to model improvement contin-
ued into the 2000s BOREAS integrated ground tower
airborne and satellite measurements of the interactions
between the forest ecosystem and the lower atmosphere
Among the key findings was the fact that atmospheric
exchanges were affected at least as much by processes in
the soil as by processes in the trees of the boreal forest
Annual carbon exchanges were found to be sensitive to
summer temperatures and especially to the timing of
snowmelt and soil freezethaw which affect soil de-
composition by microbial activity While carbon uptake
by photosynthesis is also dependent on the timing of
snowmelt and springsummer temperatures net primary
production was found to be generally more stable than
heterotropic respiration (Hall 2001) Flux measure-
ments showed that the net ecosystem exchange of car-
bon in boreal wetlands is a small residual between the
much larger uptake and respiration rates However
sensitivities are such that a warming trend accompanied
by permafrost thaw could change the boreal forest
from a long-term carbon sink to a climatically impor-
tant carbon source (Hall 2001) BOREAS contributed
to improved parameterizations of fluxes of water
(evapotranspiration) and trace gases in climate models
BOREAS measurements of forest albedo also led to
improvements of weather forecasts by the ECMWF
model (Viterbo and Betts 1999)
e GEWEXNEESPI (2000s)
The ongoing Global Energy and Water Exchanges
Project (GEWEX) program is a coordinated suite of
activities to improve understanding of the water cycle
and its interactions with the atmosphere and the land
and ocean surfaces Within its global framework
GEWEX includes the Northern Eurasia Earth Science
Partnership Initiative (NEESPI) which addresses cli-
mate and environmental change in northern Eurasia
within the water and energy cycle framework NEESPI
targets not only the regional manifestations of change
but also the impacts of these changes on the global Earth
system Over a period of a decade beginning in the early
2000s NEESPIrsquos contributions include a wide range
of atmospheric terrestrial cryospheric and socioeco-
nomic topics the aggregate of which point to a more
rapid rate of change in northern Eurasia than in other
parts of the world Changes include an earlier spring
onset and longer warmer summers which have in-
creased the strength and duration of extreme events
(drought heavy precipitation and extreme tempera-
tures) (Groisman and Gutman 2013) The increasing
temperatures and warm season duration are associated
with decreases in river ice duration (Shiklomanov and
Lammers 2014) changes in icing events (Bulygina 2015)
permafrost thaw (Streletskiy et al 2015) and shrinkage
of Russian glaciers (Khromova et al 2014) Future
projections with climate and vegetation models point to
accelerated change in climate and land surface state
(degrading permafrost) as well as the potential for
northward biome shifts of taiga vegetation into tundra
regions (Shuman et al 2015) The impacts of such
changes on ecosystems and human activity have made
the NEESPI region a target for integrated assessment
modeling (Monier et al 2017)
f SEARCH (2010s)
The ongoing Study of Environmental Arctic Change
(SEARCH) is a coordinated effort to observe un-
derstand and guide responses to changes in the Arctic
system Motivated by the recognition that interrelated
environmental changes in the Arctic are affecting eco-
systems and living resources and are having an impact on
local and global communities and economic activities the
SEARCHprogram is supported by eight federal agencies
in the United States The NSF has overseen much of the
planning and organization The framing of SEARCH is
provided by a set of overarching science questions which
are intended to bridge research and societal response
How predictable are different aspects of the Arctic sys-
tem How can improved understanding of predictability
facilitate planning mitigation and adaptation What are
the Arctic systemrsquos tipping pointsmdashthe abrupt changes
that are most consequential for ecosystems and humans
How will the critical intersections between human and
natural systems in theArctic change over the next several
decades What are the critical linkages between the
Arctic system and the global system
Among the specific targets of the early phases of
SEARCH is improved understanding of changes in sea
ice permafrost and land ice with their implications for
global sea level The goals of SEARCH also include
analysis of the societal and policy implications of Arctic
environmental change An example of a SEARCH ac-
tivity with societal applications is the Sea Ice Outlook
which has included seasonal forecasts of summer sea ice
minima by several dozen research and operational groups
(Stroeve et al 2014 2015) The Sea Ice Outlook has
stimulated work to improve forecasts of sea ice over
CHAPTER 21 WAL SH ET AL 2129
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
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1870 to 1891 Chicago International Meteorological Congress
Rep (Part II) 53 pp
Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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Allan R P Brohan G Compo R Stone J Luterbacher and
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Meteorology Proceedings of the Symposium in Melbourne
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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Barnes E A and J A Screen 2015 The impact of Arctic
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Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
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1993 Spatial and temporal variations of the intense katabatic
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Climatological aspects of cyclogenesis near Adelie Land
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mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
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Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
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Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
changing climate Environ Res Lett 10 025003 httpsdoiorg
1010881748-9326102025003
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
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over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
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Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
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Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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101002qj49706226601
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
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httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
patterns over the Ross Ice Shelf Antarctica using self-
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Summer snowfall impact on the Greenland Ice Sheet Cryo-
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
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Page J 1900 Ice and ice movements in Bering Sea during the
spring months US Hydrographic Office Rep 18 pp
Palmeacuten E 1951 The role of atmospheric disturbances in the
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mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their
Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
Quart J Roy Meteor Soc 143 2741ndash2754 httpsdoiorg
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Parish T R and D H Bromwich 1987 The surface windfield over
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mdashmdash and R Walker 2006 A re-examination of the winds of
Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117
Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
CHAPTER 21 WAL SH ET AL 2133
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
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Phillips N A 1956 The general circulation of the atmosphere A
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by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
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s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
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Screen J A and I Simmonds 2010 The central role of diminishing
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mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
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mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
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mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
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1913 Meteorology Thacker Spink amp Company 355 pp
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Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Smagorinsky J 1983 The beginnings of numerical weather pre-
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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the depletion of Antarctic ozoneNature 321 755ndash758 https
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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from Aura Microwave Limb Sounder observations Geophys
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
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Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
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Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
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Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Southern Hemisphere surface climate change Nat Geosci 4
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Thomson A 1948 The growth of meteorological knowledge of
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arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
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Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
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mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
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JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
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Untersteiner N A S Thorndike D A Rothrock and K L
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Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
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Survey during the year 1867 US Coast Survey Rep
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US National Archives 1964 Records relating to theUnited States
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CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
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1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
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van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
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THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
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von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
monthly and longer time scales (eg Stroeve et al 2014
Guemas et al 2016) The Sea Ice Outlook has included
the Sea Ice for Walrus Outlook which targets coastal
communities inAlaska The Sea IceOutlook has evolved
into the Sea Ice Prediction Network with an expanding
suite of prediction products and a growing base of con-
tributors both nationally and internationally
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ical Memoirs National Academy of Sciences 205ndash286
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1870 to 1891 Chicago International Meteorological Congress
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Alexeev V A P L Langen and J R Bates 2005 Polar ampli-
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ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24
655ndash666 httpsdoiorg101007s00382-005-0018-3
Allan R P Brohan G Compo R Stone J Luterbacher and
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Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175
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Anderson R B Bolville and D E McClellan 1955 An opera-
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Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic
Meteorology Proceedings of the Symposium in Melbourne
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Ball H L 1898 Weather Bureau Service in Alaska Mon Wea
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mwr026mwr-026-06-0254apdf
Barnes E A and J A Screen 2015 The impact of Arctic
warming on themidlatitude jet-stream Can it Has itWill it
Wiley Interdiscip Rev Climate Change 6 277ndash286 https
doiorg101002wcc337
Barr S and C Luumldecke Eds 2010 The History of the In-
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Springer-Verlag 319 pp
BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X
Barry R G 1967 Seasonal location of theArctic front over North
America Geogr Bull 9 79ndash95
Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-
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Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp
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Franccedilaise du Groenland conditions atmospheacuteriques en alti-
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entifiques No N V 119 pp
Bengtsson L V A Semenov and O M Johannessen 2004 The
early twentieth-century warming in the ArcticmdashA possible
mechanism J Climate 17 4045ndash4057 httpsdoiorg1011751520-0442(2004)0174045TETWIT20CO2
Bent S 1872 Thermal Paths to the Pole An Address Delivered
before the St Louis Mercantile Library Association RP
Studley Co 40 pp
Bessels E 1876 Scientific results of the United States Arctic ex-
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Binder H M Boettcher C M Grams H Joos S Pfahl and
H Wernli 2017 Exceptional air mass transport and dy-
namical drivers of an extreme wintertime Arctic warm
eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg
1010022017GL075841
Bindoff N L and Coauthors 2013 Detection and attribution of
climate change From global to regionalClimate Change 2013
The Physical Science Basis T F Stocker et al Eds Cam-
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Bockstoce J R and D B Botkin 1983 The historical status and re-
duction of thewesternArctic bowheadwhale (Balaenamysticetus)
population by the pelagic whaling industry 1848ndash1914 In-
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httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a
Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos
Northern Party Evidence for a relationship between winter
katabatic winds and the Terra Nova Bay polynya Polar Rec
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mdashmdash and R L Fogt 2004 Strong trends in the skill of the ERA-40
and NCEPNCAR reanalyses in the high and middle latitudes
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mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner
1993 Spatial and temporal variations of the intense katabatic
winds at Terra Nova Bay Antarctica Antarctic Meteorology
and Climatology Studies Based on Automatic Weather Sta-
tions D H Bromwich and C R Stearns Eds Antarctic
Research Series Vol 61 Amer Geophys Union 47ndash68
mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J
Hughes 2004 Polar MM5 simulations of the winter climate of the
Laurentide IceSheet at theLGM JClimate17 3415ndash3433 https
doiorg1011751520-0442(2004)0173415PMSOTW20CO2
mdashmdash KM Hines and L-S Bai 2009 Development and testing of
Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122
httpsdoiorg1010292008JD010300
mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of
precipitation changes over Antarctica and the Southern Ocean
since 1989 in contemporary global reanalyses J Climate 24
4189ndash4209 httpsdoiorg1011752011JCLI40741
mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b
Climatological aspects of cyclogenesis near Adelie Land
Antarctica Tellus 63A 921ndash938 httpsdoiorg101111
j1600-0870201100537x
mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller
G A Weidner and A B Wilson 2013 Central West Ant-
arctica among the most rapidly warming regions on Earth
Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671
mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash and mdashmdash 2014 Corrigendum
Central West Antarctica among the most rapidly warming
regions on Earth Nat Geosci 7 76 httpsdoiorg101038
ngeo2016
mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2
Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175
BAMS-D-16-02151
Brooks C E P 1938 The warming Arctic Meteor Mag 73
29ndash31
Bryson R A 1966 Air masses stream lines and the boreal forest
Geogr Bull 8 228ndash269
Bulygina O N 2015 Icing conditions over northern Eurasia in a
changing climate Environ Res Lett 10 025003 httpsdoiorg
1010881748-9326102025003
2130 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
92 (4) 429ndash522
Candlish L M R L Raddatz G G Gunn M G Asplin and
D G Barber 2013 Validation of CloudSat and CALIPSOrsquos
temperature humidity cloud detection and cloud base height
over the Arctic marine cryosphere AtmosndashOcean 51 249ndash
264 httpsdoiorg101080070559002013798582
Carruthers J N 1941 Some interrelationships of meteorology
and oceanography Quart J Roy Meteor Soc 67 207ndash246
httpsdoiorg101002qj49706729102
Cassano J J J E Box D H Bromwich L Li and K Steffen
2001 Evaluation of Polar MM5 simulations of Greenlandrsquos
atmospheric circulation J Geophys Res 106 33 867ndash33 890
httpsdoiorg1010292001JD900044
mdashmdash and Coauthors 2017 Development of the Regional Arctic
System Model (RASM) Near surface atmospheric climate
sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175
JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
1371 httpsdoiorg1011752008MWR26701
mdashmdash and mdashmdash 2010 The composite structure of tropopause polar
cyclones from a mesoscale modelMon Wea Rev 138 3840ndash
3857 httpsdoiorg1011752010MWR33711
mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
tices over the ArcticMon Wea Rev 140 1683ndash1702 https
doiorg101175MWR-D-11-001821
Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
vations and climate model constraints from CALIPSO-GOCCP
Geophys Res Lett 39 L20804 httpsdoiorg101029
2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
extreme mid-latitude weatherNat Geosci 7 627ndash637 https
doiorg101038ngeo2234
Compo G P and Coauthors 2011 The Twentieth Century Re-
analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https
doiorg101002qj776
Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816
httpsdoiorg1010022016GL071228
Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
1520-0442(1996)0091731OOACAR20CO2
Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
ment Printing Office 379ndash401 httpshdlhandlenet2027
nyp33433000204663
mdashmdash 1882 Report on the currents and temperatures of Bering
Sea and the adjacent waters US Coast and Geodetic Survey
Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue
cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
contrast and intensification or Arctic cyclones Geophys Res
Lett 45 httpsdoiorg1010292018GL077587
Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An
English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469
(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459
httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
mdashmdash and C A Schot 1859 Meteorological Observations in the
Arctic Seas Made during the Second Grinnell Expedition in
Search of Sir John Franklin in 1853 1854 and 1855 at Van
Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
513ndash521 httpsdoiorg1011751520-0469(1958)0150513
ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
doiorg105194tc-8-303-2014
Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
httpsdoiorg101016jrse201205006
Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
Denison station Adeacutelie Land Australasian Antarctic Expe-
dition 1911ndash1914 Science Rep Series B Vol 4 Government
Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
Nisbet 2011 Sea-ice distribution in the Bering and Chukchi
Seas Information from historical whaleshipsrsquo logbooks and
journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146
Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
Radiation Regime of the Arctic Basin (from the Drifting Sta-
tions) Hydrometeorological Publishing House 63 pp
Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
Direct Aerosol Campaign (ISDAC) The impact of Arctic
aerosols on clouds Bull Amer Meteor Soc 92 183ndash201
httpsdoiorg1011752010BAMS29351
Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
on biology and human activity Rev Geophys 52 185ndash217
httpsdoiorg1010022013RG000431
Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
Lett 12 083001 httpsdoiorg1010881748-9326aa7aae
Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
doiorg1010800043167219589925043
Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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doiorg101175MWR-D-13-003821
Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
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Pettersen S 1950 Some aspects of the general circulation of the
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Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
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Powers J K W Manning D H Bromwich J J Cassano and
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
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Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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Rusin N P 1964 Meteorological and Radiational Regime of
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
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Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
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Screen J A and I Simmonds 2010 The central role of diminishing
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mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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Skamarock W C 2004 Evaluating mesoscale NWP models us-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
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Thomson A 1948 The growth of meteorological knowledge of
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Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
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Walker G T 1923 Correlation in seasonal variation of weather
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Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
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Wood K R and J E Overland 2006 Climate lessons from the
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Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
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Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
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Zhang J R Lindsey A Schweiger and M Steele 2013 The
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Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
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Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag
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Candlish L M R L Raddatz G G Gunn M G Asplin and
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Carruthers J N 1941 Some interrelationships of meteorology
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Cassano J J J E Box D H Bromwich L Li and K Steffen
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mdashmdash and Coauthors 2017 Development of the Regional Arctic
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JCLI-D-15-07751
Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis
of a tropopause polar cyclone Mon Wea Rev 137 1358ndash
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mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-
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Cesana G J E Kay H Chepfer J English andG de Boer 2012
Ubiquitous low-level liquid-containing Arctic clouds New obser-
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2012GL053385
Cohen J and Coauthors 2014 Recent Arctic amplification and
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Compo G P and Coauthors 2011 The Twentieth Century Re-
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Crawford A and M C Serreze 2015 A new look at the Arctic
frontal zone J Climate 28 737ndash754 httpsdoiorg101175
JCLI-D-14-004471
mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence
Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https
doiorg101175JCLI-D-15-07551
mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone
and summer Arctic cyclone activity in the CESM Large En-
semble J Climate 30 9847ndash9869 httpsdoiorg101175
JCLI-D-17-02961
Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee
and S M J Nowicki 2016 Analysis of the warmest Arctic
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Curry J A E E Ebert and J L Schramm 1993 Impact of clouds
on the surface radiation balance of the Arctic Ocean Meteor
Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494
mdashmdash W B Rossow D Randall and J L Schramm 1996
Overview of Arctic cloud and radiation characteris-
tics J Climate 9 1731ndash1764 httpsdoiorg101175
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Dall W H 1879 Appendix I Meteorology Coast Pilot of
Alaska US Coast and Geodetic Survey Rep Govern-
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nyp33433000204663
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Sea and the adjacent waters US Coast and Geodetic Survey
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cgs002_pdfCSC-0079PDF
Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de
Arktiske Have (The state of the ice in the Arctic seas) I
Kommission Hos GEC Gad
mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the
ice in the Arctic seas) I Kommission Hos GEC Gad
Day J J and K I Hodges 2018 Growing landndashsea temperature
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Deb P A Orr D H Bromwich J P Nicolas J Turner and J S
Hosking 2018 Summer drivers of atmospheric variability af-
fecting ice shelf thinning in the Amundsen Sea Embayment
West Antarctica Geophys Res Lett 45 4124ndash4133 https
doiorg1010292018GL077092
de Boer G W Chapman J Kay B Medeiros M D Shupe
S Vavrus and J E Walsh 2012 A characterization of the
Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695
httpsdoiorg101175JCLI-D-11-002281
De Long G W 1884 The Voyage of the Jeannette The Ship and
Ice Journals of George W De Long Lieutenant-Commander
USN and Commander of the Polar Expedition of 1879ndash1881
Vols 1 and 2 Houghton Mifflin 911 pp
Dorsey H G Jr 1945 Some meteorological aspects of the
Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg
1011751520-0469(1945)0020135SMAOTG20CO2
Douglass A P Newman and S Solomon 2014 The Antarctic
ozone hole An update Phys Today 67 42 httpsdoiorg
101063PT32449
DuVivier A K and J J Cassano 2013 Evaluation of WRF
Model resolution on simulated mesoscale winds and surface
fluxes near Greenland Mon Wea Rev 141 941ndash963 https
doiorg101175MWR-D-12-000911
mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen
R Osinski and A Roberts 2016 Winter atmospheric buoy-
ancy forcing and oceanic response during strong wind events
around southeasternGreenland in theRegionalArctic System
Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https
doiorg101175JCLI-D-15-05921
Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere
Tsentralnoi Arktiki (Circulation schemes for the central
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English translation is available in UCLA Meteorology Dept
Scientific Report No 3 under Contract AF19(122)-228)
Exner F M 1913 Uumlber monatliche Witterunganomalien auf der
noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies
in the Northern Hemisphere in winter) Sitzungberichte der
Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240
Farman J C B G Gardiner and J D Shanklin 1985 Large
losses of total ozone in Antarctica reveal seasonal CLOx
NOx interaction Nature 315 207ndash210 httpsdoiorg101038
315207a0
Ferrel W 1875 On the mechanics and the general motions of the
atmosphere Part I Meteorological researches for the use of
the coast pilot US Coast Survey Rep 64 pp
Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash
2015 Greenland ice sheet surface mass balance using the re-
gional climate MAR model Cryosphere 11 1015ndash1033
httpsdoiorg105194tc-11-1015-2017
FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska
Arranged from the Directory of the Pacific Ocean Bureau of
CHAPTER 21 WAL SH ET AL 2131
Navigation Rep Government Printing Office 193 pp https
babelhathitrustorgcgiptid5hvd32044080604465
Fletcher J O 1965 The heat budget of the Arctic Basin and its
relation to climate RAND Corporation Rep R-444-PR 179
pp httpswwwrandorgpubsreportsR0444html
Fogt R L M E Jones S Solomon J M Jones and C A
Goergens 2017 An exceptional summer during the South
Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199
httpsdoiorg101175BAMS-D-17-00131
Francis J A and S J Vavrus 2012 Evidence linking Arctic
amplification to extreme weather in mid-latitudes Geophys
Res Lett 39 L06801 httpsdoiorg1010292012GL051000
Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
37 2211ndash2232 httpsdoiorg101002joc4775
Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes
in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg
101002qj2401
Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg
101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029
2001JD001526
Hare F K 1960a The disturbed circulation of the Arctic strato-
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(1960)0170036TDCOTA20CO2
mdashmdash 1960b The summer circulation of the Arctic stratosphere
below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https
doiorg101002qj49708636802
mdashmdash 1961 The circulation of the stratosphere McGill University
Arctic Meteorology Research Group Publ 43 54 pp
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httpsdoiorg101002qj49709440202
mdashmdash and S Orvig 1958 The Arctic circulation A preliminary
view McGill University Arctic Meteorology Research Group
Publ 12 McGill University 211 pp
mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr
Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
[154MWIA]20CO2
Hines KM andD H Bromwich 2017 Simulation of late summer
Arctic clouds duringASCOSwith PolarWRFMonWea Rev
145 521ndash541 httpsdoiorg101175MWR-D-16-00791
Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric
Circulation MacMillan 198 pp
mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2
143ndash153 httpsdoiorg1011751520-0469(1945)0020135
TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
H T Hewitt 2013 Identifying uncertainties in Arctic climate
change projections Climate Dyn 40 2849ndash2865 https
doiorg101007s00382-012-1512-z
Hollingsworth A 1989 The Global Weather Experimentmdash10
years on Weather 44 278ndash285 httpsdoiorg101002j1477-
86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
steamer Corwin in the Arctic Ocean US Treasury Doc 118
Government Printing Office 71 pp httpsbabelhathitrust
orgcgiptid5mdp39015059478647
Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
2003 An overview of the North Atlantic Oscillation
The North Atlantic Oscillation Climatic Significance and
Environmental ImpactGeophys Monogr Vol 134 Amer
Geophys Union 1ndash35
Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
doiorg1011751520-0493(1922)50589aTCA20CO2
Jessup D E 2007 Connecting Alaska The Washington-Alaska
Military Cable and Telegraph System J Gilded Age Prog
Era 6 385ndash408 httpsdoiorg101017S1537781400002218
Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
BF01054476
Jung T and Coauthors 2016 Advancing polar prediction
capabilities on daily to seasonal time scales Bull Amer
Meteor Soc 97 1631ndash1647 httpsdoiorg101175
BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg
1011751520-0477(1992)0731824ISMSAF20CO2
Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
Franklin A Personal Narrative Harper and Brothers 552 pp
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Rensselaer Harbor and Other Points on the West Coast of
Greenland Smithsonian Institution 112 pp
Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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ASAIW20CO2
Khromova T G Nosenko S Kutuzov A Muraviev and
L Chernova 2014 Glacier area change in northern Eurasia
Environ Res Lett 9 015003 httpsdoiorg1010881748-9326
91015003
Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
in the central Arctic Ocean Cryosphere 8 303ndash317 https
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
understanding-earths-polar-challenges-international-polar-
year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
Cassano 2012 Antarctic automatic weather station program
30 years of polar observations Bull Amer Meteor Soc 93
1519ndash1537 httpsdoiorg101175BAMS-D-11-000151
2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
Sat and CALIPSO Remote Sens Environ 124 159ndash173
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg
101002qj49706226601
mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-
teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711
Madigan C T 1929 Tabulated and reduced records of the Cape
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Printer 28 pp
Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
CO2 concentration on the climate of a general circulation
model J Atmos Sci 32 3ndash15 httpsdoiorg101175
1520-0469(1975)0320003TEODTC20CO2
mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology
of general circulation with a hydrologic cycle Mon Wea Rev
93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769
SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004
Polynya dynamics A review of observations and modelingRev
Geophys 42 RG1004 httpsdoiorg1010292002RG000116
Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
101029TR027i003p00324
mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-
ined in light of recent meteorological data fromGreenlandmdashPart
2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg
101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
William Heinemann 687 pp
McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
Glacier West Antarctica confirm the spatio-temporal vari-
ability of global and regional atmospheric models Geophys
Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706
Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
Central at Little America Weatherwise 11 196ndash200 https
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in
North America Polar Sci 16 1ndash9 httpsdoiorg101016
jpolar201802001
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Page J 1900 Ice and ice movements in Bering Sea during the
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Palmeacuten E 1951 The role of atmospheric disturbances in the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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CHAPTER 21 WAL SH ET AL 2133
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2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
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cause climate model biases in Arctic wintertime temperature
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s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
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1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
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SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
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Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
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AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
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Screen J A and I Simmonds 2010 The central role of diminishing
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mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
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SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
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TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
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Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
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and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
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mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
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Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
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Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
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mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
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Simpson E 1890 Report of ice and ice movements in Bering Sea
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
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1913 Meteorology Thacker Spink amp Company 355 pp
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1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
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Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
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Stolarski R S A J Krueger M R Shoeberl R D McPeters
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measurements of the springtime Antarctic ozone decrease
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Strahan S E and A R Douglass 2018 Decline in Antarctic
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from Aura Microwave Limb Sounder observations Geophys
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Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
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Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
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Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
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doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
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Southern Hemisphere surface climate change Nat Geosci 4
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Thomson A 1948 The growth of meteorological knowledge of
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arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
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Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
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Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
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JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
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CHAPTER 21 WAL SH ET AL 2135
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van Loon H 1967 The half-yearly oscillations in middle and high
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THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
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Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
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Walker G T 1923 Correlation in seasonal variation of weather
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Wiese W 1924 Polareis und Atmospharische Schwankungen
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Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
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Wood K R and J E Overland 2006 Climate lessons from the
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Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
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Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
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Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
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Francis J A and S J Vavrus 2012 Evidence linking Arctic
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Freeman E and Coauthors 2016 ICOADS release 30 A major
update to the historical marine climate record Int J Climatol
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Fyfe J C K von Salzen N P Gillett V K Arora G Flato and
J R McConnell 2013 One hundred years of Arctic surface
temperature variation due to anthropogenic influenceNature
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in Siberia Regional Changes and Their Global Consequences
Springer 360 pp httpsdoiorg101007978-94-007-4569-8
Guemas V and Coauthors 2016 A review on Arctic sea-ice
predictability and prediction on seasonal to decadal time-
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Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone
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101175JAS-33531
Hall F G 2001 Introduction to special section BOREAS III
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Hare F K 1960a The disturbed circulation of the Arctic strato-
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Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of
Discovery towards the North Pole in the Schooner lsquolsquoUnited
Statesrsquorsquo Sampson Low 454 pp
Henry A J 1898 Meteorological work in Alaska Mon Wea
Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26
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Hines KM andD H Bromwich 2017 Simulation of late summer
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Hobbs W H 1910 Characteristics of the inland ice of the Arctic
regions Proc Amer Philos Soc 49 57ndash129
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Circulation MacMillan 198 pp
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TGGA20CO2
Hodson D S P E Keeley A West J Ridley E Hawkins and
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Hollingsworth A 1989 The Global Weather Experimentmdash10
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86961989tb07053x
Hooper C L 1881 Report of the cruise of the US Revenue-
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Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds
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Ifft GN 1922 The changingArcticMonWea Rev 50 589 https
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Jessup D E 2007 Connecting Alaska The Washington-Alaska
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Jones P D 1987 The twentieth century Arctic highmdashFact or
fiction Climate Dyn 1 63ndash75 httpsdoiorg101007
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Jung T and Coauthors 2016 Advancing polar prediction
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BAMS-D-14-002461
Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell
1992 In situ meteorological sounding archives for Arctic stud-
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Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John
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Keegan T J 1958Arctic synoptic activity in winter JMeteor 15
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Kim B-M and Coauthors 2017 Major cause of unprecedented
Arctic warming in January 2016 Critical role of an Atlantic
windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051
Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice
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Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar
Challenges International Polar Year 2007ndash2008 International
Science Council 695 pp httpscouncilsciencepublications
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year-2007-2008
Laursen V 1959 The second International Polar Year Annals of
the International Geophysical Year Vol 1 Pergamon 211ndash234
Lazzara M A G A Weidner L M Keller J E Thom and J C
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30 years of polar observations Bull Amer Meteor Soc 93
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2132 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
in the Arctic J Climate 27 2588ndash2606 httpsdoiorg
101175JCLI-D-13-000141
Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Mahoney A R J R Bockstoce D B Botkin H Eicken andRA
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Manabe S and R Wetherald 1975 The effects of doubling the
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of general circulation with a hydrologic cycle Mon Wea Rev
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SCOAGC23CO2
ManleyG 1944 Some recent contributions to the study of climate
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Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
light of recent meteorological data from GreenlandmdashPart I
Trans Amer Geophys Union 27 324ndash341 httpsdoiorg
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ined in light of recent meteorological data fromGreenlandmdashPart
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101029TR031i002p00174
Mawson D 1915 The Home of the Blizzard Vols 1 and 2
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McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
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Meier W N and Coauthors 2014 Arctic sea ice in trans-
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Monier E and Coauthors 2017 A review of and perspectives on
global change modeling for northern Eurasia Environ Res
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
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Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Nigro M A and J J Cassano 2014 Identification of surface wind
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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Page J 1900 Ice and ice movements in Bering Sea during the
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Palmeacuten E 1951 The role of atmospheric disturbances in the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
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Pettersen S 1950 Some aspects of the general circulation of the
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
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cause climate model biases in Arctic wintertime temperature
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Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
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AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
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1520-0450(1994)0330948AORFAC20CO2
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certainty in modeled Arctic sea ice volume J Geophys Res
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Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
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Screen J A and I Simmonds 2010 The central role of diminishing
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mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
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TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
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Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
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physical properties J Appl Meteor Climatol 50 626ndash644
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Challenge of Arctic clouds and their implications for surface
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Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
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Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
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and Arctic Basin US Hydrographic Office Rep 92 25 pp
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Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
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1913 Meteorology Thacker Spink amp Company 355 pp
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Smirnova J and P Golubkin 2017 Comparing polar lows in at-
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Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
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Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
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Stroeve J L C Hamilton C M Bitz and E Blanchard-
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Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
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Taylor P C M Cai A Hu J Meehl W Washington and G J
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doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
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ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
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Southern Hemisphere surface climate change Nat Geosci 4
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Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
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Washington Rep 131 pp httpiabpaplwashingtonedupdfs
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Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
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Centre sea ice and sea surface temperature data set version 2
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Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
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Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
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JCLI-D-15-06511
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Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
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CHAPTER 21 WAL SH ET AL 2135
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1011751520-0477(2002)0830255SHBOTA23CO2
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van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
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THYOIM20CO2
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J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
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Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
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Vernon C L J L Bamber J E Box M R van den Broeke
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balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
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von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
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Vowinckel E and S Orvig 1971 The Climate of the North Polar
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Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
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temperature associations in observational data and atmo-
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Wood K R and J E Overland 2006 Climate lessons from the
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Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
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Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
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Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
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Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
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2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Lindsay R M Wensnahan A Schweiger and J Zhang 2014
Evaluation of seven different atmospheric reanalysis products
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Liu Y J R Key S A Ackerman G G Mace and Q Zhang
2012 Arctic cloud macrophysical characteristics from Cloud-
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Loewe F 1936 TheGreenland ice cap as seen by a meteorologist
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Madigan C T 1929 Tabulated and reduced records of the Cape
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Manabe S and R Wetherald 1975 The effects of doubling the
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ManleyG 1944 Some recent contributions to the study of climate
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Marshunova M S and A A Mishin 1994 Handbook on the
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Matthes F E 1946 The glacial anticyclone theory examined in
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ined in light of recent meteorological data fromGreenlandmdashPart
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Mawson D 1915 The Home of the Blizzard Vols 1 and 2
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McFarquhar G M and Coauthors 2011 Indirect and Semi-
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Medley B and Coauthors 2013 Airborne-radar and ice-core
observations of annual snow accumulation over Thwaites
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ability of global and regional atmospheric models Geophys
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Meier W N and Coauthors 2014 Arctic sea ice in trans-
formation A review of recent observed changes and impacts
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Monier E and Coauthors 2017 A review of and perspectives on
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Moreland W B 1958 Inside Antarctica No 3mdashThe Weather
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Namias J 1958 The general circulation of the lower troposphere
over Arctic regions and its relation to the general circulation
elsewhere Meteorology Part I Polar Atmosphere Sympo-
sium Pergamon Press 45ndash61
Nansen F 1898 Farthest North Being the Record of a Voyage of
Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen
Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen
Vol 1 Harper amp Brothers 587 pp
Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in
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Newton C W Ed 1972 Meteorology of the Southern Hemi-
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Nicolas J P and D H Bromwich 2011 Climate of West Ant-
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Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke
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Overland J E and M Wang 2016 Recent extreme Arctic tem-
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Page J 1900 Ice and ice movements in Bering Sea during the
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Structure and Physical Interpretation Academic Press 603 pp
Palo T TVihma J Jaagus andE Jakobson 2017Observations of
temperature inversions over central Arctic sea ice in summer
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Parish T R and D H Bromwich 1987 The surface windfield over
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Parkinson C L and J C Comiso 2013 On the 2012 record low
Arctic sea ice cover Geophys Res Lett 40 1356ndash1361
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Penner C M 1955 A three-front model for synoptic analyses
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Persson P O G 2012 Onset and end of the summer melt season
over sea ice Thermal structure and surface energy perspective
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Pettersen S 1950 Some aspects of the general circulation of the
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Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
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Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
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s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
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Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
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Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
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Rae R W 1951 The Climate of the Canadian Archipelago Tor-
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Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
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Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
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Rinke A M Maturilli R M Graham H Matthes D Handorf
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Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
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101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
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changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
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id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
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certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
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Screen J A and I Simmonds 2010 The central role of diminishing
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mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
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Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg
101007s00382-011-1196-9
mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich
2002 Measurements near the atmospheric surface group
tower at SHEBA Near-surface conditions and surface energy
budget J Geophys Res 107 8045 httpsdoiorg101029
2000JC000705
Pettersen S 1950 Some aspects of the general circulation of the
atmosphere Centenary Proceedings of the Royal Meteoro-
logical Society Royal Meteorological Society 120ndash153
Phillips N A 1956 The general circulation of the atmosphere A
numerical experiment Quart J Roy Meteor Soc 82 123ndash
164 httpsdoiorg101002qj49708235202
Pithan F and T Mauritsen 2014 Arctic amplification dominated
by temperature feedbacks in contemporary climate models
Nat Geosci 7 181ndash184 httpsdoiorg101038ngeo2071
mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds
cause climate model biases in Arctic wintertime temperature
inversions Climate Dyn 43 289ndash303 httpsdoiorg101007
s00382-013-1964-9
Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-
analysis of the Twentieth Century J Climate 29 4083ndash4097
httpsdoiorg101175JCLI-D-15-05561
Polyakov I V and Coauthors 2003 Long-term ice variability in
Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg
1011751520-0442(2003)0162078LIVIAM20CO2
Powers J K W Manning D H Bromwich J J Cassano and
A M Cayette 2012 A decade of Antarctic science support
through AMPS Bull Amer Meteor Soc 93 1699ndash1712
httpsdoiorg101175BAMS-D-11-001861
Rae R W 1951 The Climate of the Canadian Archipelago Tor-
onto Department of Transport 90 pp
Reed R J and B A Kunkel 1960 The arctic circulation in
summer J Meteor 17 489ndash506 httpsdoiorg101175
1520-0469(1960)0170489TACIS20CO2
Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and
Francis 1272 pp
Ringgold C and J Rodgers 1950 United States North Pacific
Exploring Expedition under Commanders Ringgold and
Rodgers 1853-1856 Biodiversity Heritage Library 8 pp
httpsdoiorg105962bhltitle147272
Rinke A M Maturilli R M Graham H Matthes D Handorf
L Cohen S R Hudson and J C Moore 2017 Extreme
cyclone events in the Arctic Wintertime variability and
trends Environ Res Lett 12 094006 httpsdoiorg101088
1748-9326aa7def
Rodionov S N J E Overland and N A Bond 2005 The
Aleutian low and winter climatic conditions in the Bering Sea
Part I Classification J Climate 18 160ndash177 httpsdoiorg
101175JCLI32531
Rusin N P 1964 Meteorological and Radiational Regime of
Antarctica Israel Program for Scientific Translations 355 pp
Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber
Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100
mdashmdash 1960 Stratospheric temperature changes and the associated
changes in pressure distribution J Meteor 17 575ndash582 https
doiorg1011751520-0469(1960)0170575STCATA20CO2
SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep
GovernmentPrintingOffice 75pphttpsbooksgooglecombooks
id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_
summary_rampcad50v5onepageampqampf5false
Schlosser E B Stenni M Valt A Cagnati J G Powers K W
Manning M Raphael and M G Duda 2016 Precipitation and
synoptic regime in two extreme years 2009 and 2010 at Dome C
AntarcticamdashImplications for ice core interpretationAtmos Chem
Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM
aircraft measurements The Atmospheric Radiation Mea-
surement (ARM) Program The First 20 Years Meteor
Monogr No 57 Amer Meteor Soc httpsdoiorg101175
AMSMONOGRAPHS-D-15-00421
Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes
and cloud forcing from the ISCCP C2 cloud dataset 1983ndash
1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175
1520-0450(1994)0330948AORFAC20CO2
mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-
certainty in modeled Arctic sea ice volume J Geophys Res
116 C00D06 httpsdoiorg1010292011JC007084
Schwerdtfeger W 1970 The climate of the Antarctic Climates of
the Polar Regions S Orvig EdWorld Survey of Climatology
Vol 14 Elsevier 253ndash355
mdashmdash 1972 The vertical variation of the wind through the friction-
layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg
103402tellusav24i110615
Screen J A and I Simmonds 2010 The central role of diminishing
sea ice in recent Arctic temperature amplification Nature 464
1334ndash1337 httpsdoiorg101038Znature09051
mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-
spheric response to Arctic sea-ice loss across climate modelsNat
Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y
SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal
zone as seen in the NCEPndashNCAR Reanalysis J Climate
14 1550ndash156 httpsdoiorg1011751520-0442(2001)0141550
TAFZAS20CO2
mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland
2009 The emergence of surface-based Arctic amplification
Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009
Shapiro M A T Hampel and A J Krueger 1987 The Arctic
tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg
1011751520-0493(1987)1150444TATF20CO2
Shiklomanov A I and R B Lammers 2014 River ice re-
sponses to a warming ArcticmdashRecent evidence from Rus-
sian rivers Environ Res Lett 9 035008 httpsdoiorg
1010881748-932693035008
Shuman J K NM Tchebakova E I Parfenova A J Soja H H
Shugart D Ershov and K Holcomb 2015 Forest forecasting
with vegetation models across Russia Can J For Res 45
175ndash184 httpsdoiorg101139cjfr-2014-0138
Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the
Arctic surface The influence of cloud properties surface albedo
and solar zenith angle J Climate 17 616ndash628 httpsdoiorg
1011751520-0442(2004)0170616CRFOTA20CO2
mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M
Starkweather and M Shiobara 2011 Clouds at Arctic at-
mospheric observatories Part I Occurrence and macro-
physical properties J Appl Meteor Climatol 50 626ndash644
httpsdoiorg1011752010JAMC24671
mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]
Challenge of Arctic clouds and their implications for surface
radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer
Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg
doisuppl1011752015BAMSStateoftheClimate1suppl_
file101175_2015BAMSStateoftheClimate3pdf
mdashmdash and Coauthors 2016 MOSAiC science plan International
Arctic Science Committee Rep 85 pp httpswwwmosaic-
2134 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
expeditionorgfileadminuser_uploadMOSAiCDocuments
MOSAiC_SciencePlan-V20pdf
Simmonds I and K Keay 2009 Extraordinary Arctic sea ice
reductions and their relationships with storm behavior over
1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg
1010292009GL039810
mdashmdash and I Rudeva 2012 The great Arctic cyclone of August
2012 Geophys Res Lett 39 L23709 httpsdoiorg101029
2012GL054259
Simpson E 1890 Report of ice and ice movements in Bering Sea
and Arctic Basin US Hydrographic Office Rep 92 25 pp
httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53
Simpson G C 1919 Weather Maps and Pressure Curves Vol II
British Antarctic Expedition 1910ndash1913 Meteorology Thacker
Spink amp Company 138 pp
mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink amp Company 355 pp
mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash
1913 Meteorology Thacker Spink and Company 848 pp
Skamarock W C 2004 Evaluating mesoscale NWP models us-
ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032
httpsdoiorg101175MWR28301
Smagorinsky J 1983 The beginnings of numerical weather pre-
diction and general circulation modeling Early recollections
Advances in Geophysics Vol 25 Academic Press 3ndash37
httpsdoiorg101016S0065-2687(08)60170-3
Smirnova J and P Golubkin 2017 Comparing polar lows in at-
mospheric reanalyses Arctic System Reanalysis versus ERA-
Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg
101175MWR-D-16-03331
Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-
pedition Yale University Press 383 pp
mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On
the depletion of Antarctic ozoneNature 321 755ndash758 https
doiorg101038321755a0
Stolarski R S A J Krueger M R Shoeberl R D McPeters
P A Newman and J C Alpert 1986 Nimbus 7 satellite
measurements of the springtime Antarctic ozone decrease
Nature 322 808ndash811 httpsdoiorg101038322808a0
Strahan S E and A R Douglass 2018 Decline in Antarctic
ozone depletion and lower stratospheric chlorine determined
from Aura Microwave Limb Sounder observations Geophys
Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830
Stramler K A D Del Genio and W B Rossow 2011 Synopti-
cally driven Arctic winter states J Climate 24 1747ndash1762
httpsdoiorg1011752010JCLI38171
Streletskiy D A A B Sherstiukov O W Fraunfeld and F E
Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-
mal regime in Russian permafrost regions Environ Res Lett
10 125005 httpsdoiorg1010881748-93261012125005
Stroeve J L C Hamilton C M Bitz and E Blanchard-
Wrigglesworth 2014 Predicting September sea ice Ensemble
skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res
Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388
mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell
F Massonnet and S Tietsche 2015 Improving predictions of
Arctic sea ice extent Eos Trans Amer Geophys Union 96
httpsdoiorg1010292015EO031431
Taylor P C M Cai A Hu J Meehl W Washington and G J
Zhang 2013 A decomposition of feedback contributions to
polar warming amplification J Climate 26 7023ndash7043 https
doiorg101175JCLI-D-12-006961
Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et
recherches sur lrsquoinfluence de la position des grands centres
drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on
the winter of 1879ndash80 and research on the influence of the
position of the great atmospheric centers of action in abnormal
winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-
logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https
doiorg1010800004697319719648324
ThompsonDW J and S Solomon 2002 Interpretation of recent
Southern Hemisphere climate change Science 296 895ndash899
httpsdoiorg101126science1069270
mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J
Karoly 2011 Signatures of the Antarctic ozone hole in
Southern Hemisphere surface climate change Nat Geosci 4
741ndash749 httpsdoiorg101038ngeo1296
Thomson A 1948 The growth of meteorological knowledge of
the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430
arctic3995
ThorndikeA S andRColony 1981ArcticOceanBuoy Program
DataReport 1 January 1980ndash31December 1980 University of
Washington Rep 131 pp httpiabpaplwashingtonedupdfs
AOBP1980Thorndikepdf
Timmermans M L J Toole and R Krishfield 2018Warming of the
interior Arctic Ocean linked to sea ice losses at the basin margins
Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773
Titchner H A and N A Rayner 2014 The Met Office Hadley
Centre sea ice and sea surface temperature data set version 2
1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash
2889 httpsdoiorg1010022013JD020316
Tjernstrom M J Sedlar and M D Shupe 2008 How well do
regional climate models reproduce radiation and clouds in
the Arctic An evaluation of ARCMIP simulations J Appl
Meteor Climatol 47 2405ndash2422 httpsdoiorg101175
2008JAMC18451
mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean
Study (ASCOS) Overview and experimental design At-
mos Chem Phys 14 2823ndash2869 httpsdoiorg105194
acp-14-2823-2014
Tomas R A C Deser and L Sun 2016 The role of ocean heat
transport in the global climate response to projected Arctic
sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175
JCLI-D-15-06511
Tyson G E and H W Howgate 1879 The Cruise of the Florence
or Extracts from the Journal of the PreliminaryArctic Expedition
of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg
cgiptid5aeuark13960t46q2g92jview51upseq57
Untersteiner N A S Thorndike D A Rothrock and K L
Hunkins 2009 AIDJEX revisited A look back at the US-
Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78
Arctic 60 327ndash336 httpsdoiorg1014430arctic233
US Coast Survey 1869 Report of the superintendent of the
United States Coast Survey showing the progress of the
Survey during the year 1867 US Coast Survey Rep
334 pp
US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-
sphere Vol 550 US Hydrographic Office 106 pp
US National Archives 1964 Records relating to theUnited States
surveying expedition to the North Pacific Ocean 1852ndash1863
National Archives and Records Service General Services
Administration Microfilm
CHAPTER 21 WAL SH ET AL 2135
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59
Uttal T and Coauthors 2002 Surface heat budget of the Arctic
Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg
1011751520-0477(2002)0830255SHBOTA23CO2
van de Berg W J M R van den Broeke C H Reijmer and
E van Meijgaard 2005 Characteristics of Antarctic surface
mass balance 1958ndash2002 using a regional atmospheric climate
model Ann Glaciol 41 97ndash104 httpsdoiorg103189
172756405781813302
van Loon H 1967 The half-yearly oscillations in middle and high
southern latitudes and the coreless winter J Atmos Sci
24 472ndash486 httpsdoiorg1011751520-0469(1967)0240472
THYOIM20CO2
Vavrus S J F Wang J E Martin J A Francis Y Peings and
J Cattiaux 2017 Changes in North American atmospheric
circulation and extreme weather Influence of Arctic amplifi-
cation and Northern Hemisphere snow cover J Climate 30
4317ndash4333 httpsdoiorg101175JCLI-D-16-07621
Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud
Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205
Vernon C L J L Bamber J E Box M R van den Broeke
X Fettweis E Hanna and P Huybrechts 2013 Surface mass
balance model intercomparison for the Greenland ice sheet
Cryosphere 7 599ndash614 httpsdoiorg105194tc-7-599-2013
Viterbo P and A K Betts 1999 The impact on ECMWF fore-
casts of changes in the albedo of the boreal forests in the
presence of snow J Geophys Res 104 27 803ndash27 810 https
doiorg1010291998JD200076
von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On
atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program
to study arctic hydrology and its role in global change Eos
Trans Amer Geophys Union 83 241ndash249 httpsdoiorg
1010292002EO000167
Vowinckel E and S Orvig 1971 The Climate of the North Polar
Basin Climates of the Polar Regions S Orvig Ed World
Survey of Climatology Vol 14 Elsevier 129ndash252
Walker G T 1923 Correlation in seasonal variation of weather
VIII A preliminary study of world weather Mem Indian
Meteor Dep 24 75ndash131
Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash
temperature associations in observational data and atmo-
spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg
1011751520-0442(1998)0113030ACRTAI20CO2
mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-
vational data Ann Glaciol 33 444ndash448 httpsdoiorg
103189172756401781818671
mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database
for depicting Arctic sea ice variations back to 1850Geogr Rev
107 89ndash107 httpsdoiorg101111j1931-0846201612195x
Wang G and W Cai 2013 Climate-change impact on the 20th-
century relationship between the southern annular mode and
global mean temperature Sci Rep 3 2039 httpsdoiorg
101038srep02039
Weather Bureau 1925 Climatological data herein from the es-
tablishment of the stations to 1921 inclusive USDepartment
of Agriculture Rep 277 pp
Weingartner T J S Danielson Y Sasaki V Pavlov and
M Kulakov 1999 The Siberian Coastal Current A wind- and
buoyancy-forcedArctic coastal current JGeophys ResOceans
104 29 697ndash29 713 httpsdoiorg1010291999JC900161
Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-
Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut
Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-
schaftlichen Beobachtungen gehalten in Wien 18 Januar
1875 (The second Austro-Hungarian Arctic Expedition under
Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos
lecture on his scientific observations held in Vienna 18 Janu-
ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer
Anstalt Vol 21 65ndash72
Wiese W 1924 Polareis und Atmospharische Schwankungen
(Polar ice and atmospheric fluctuations) Geogr Ann 6
273ndash299
Wilkes C 1845a Narrative of the United States Exploring Ex-
pedition during the Years 1838 1839 1840 1841 1842 Vol
1 Lea and Blanchard 434 pp httpsarchiveorgdetails
narrativeofunite01wilkuoftpagen0
mdashmdash 1845b Narrative of the United States Exploring Expedi-
tion during the Years 1838 1839 1840 1841 1842 Vol 4
Lea and Blanchard 539 pp httpsarchiveorgdetails
narrativeofunite04wilkuoftpagen0
Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-
sphere during 1955 McGill University Arctic Meteorology
Research Group Publ 8 57 pp
Wood K R and J E Overland 2006 Climate lessons from the
first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685
mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-
spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973
Woodgate R A K Aagaard and T J Weingartner 2005
Monthly temperature salinity and transport variability of the
Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880
Yamanouchi T 2011 Early 20th century warming in the Arctic A re-
viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002
Zhang J R Lindsey A Schweiger and M Steele 2013 The
impact of an intense summer cyclone on 2012 Arctic sea
ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg
101002grl50190
Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012
Arctic clouds and surface radiationmdashA critical comparison of
satellite retrievals and theERA-Interim reanalysisAtmos Chem
Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012
2136 METEOROLOG ICAL MONOGRAPHS VOLUME 59