Scientific Issues of Scientific Issues of AMY08AMY08
Atmosphere-Atmosphere-OOcean-cean-LLand and
IInteractionnteraction-Part I-Part I
Guoxiong WU
3 September, 2007 Bali, Indonesia
1. Science Significance
2. Energy and water cycle
3. Land-air-sea interaction
4. Science Issues
Outlines
Monsoon and Monsoon and the Year of Tropical Convectionthe Year of Tropical Convection
-WCRP JSC-XXVIII-WCRP JSC-XXVIII
Guoxiong WU, Richard Lawford and Howard Cattle
27 March, 2007 Zanzibar
Monsoon- one of the central components of the
climate system:
influence the global climate system
has distinct regional characteristics
Monsoonal circulations dominate south and east
Asia and are also significant in Africa and the
Americas.
1. Science Significance
NDVI image for 21-31 August 2000, from Pathfinder AVHRR
EAM
WAM
Major monsoons systems of the world
IM
AUM
SAMS
NAMS
NDVI surface vegetation
AMY08
Africa: AMMA ‘s focus on West African Monsoon
(WAM) and its variability with an emphasis on daily-
inter-annual timescales;
Asia-Australia : directed at understanding the processes
responsible for the onset, evolution and termination of
the monsoon
Americas : emphasizes the determination of the sources
and limits of predictability of warm season
precipitation.
CLIVAR and GEWEX coordinate studies in the three primary monsoon
regions
Monsoons
Presentations were made by G. Wu (assisted by R. Lawford and H. Cattle), Yasunari and
J. Shukla.
Main points of discussion are as follows:
• There is a large number of national and multi-national monsoon programmes and activities.
The idea of holding an International Monsoon Year (as component of an International
Monsoon Study 2007-2011) created interest and the support of the JSC….….
• It was recommended that a short term task team (one year) be appointed (Chairs B. Wang and
J. Matsumoto) to develop a 5 year Implementation Plan, building on and integrating the
existing plans for Year of Tropical Convection (YOTC) (joint with THORPEX), the
Asian Monsoon Year and to ensure the monsoon data sets are exchanged and
appropriately archived and that the appropriate modelling studies are pursued….
• The consensus was that the crosscut should be deeply rooted in CLIVAR and GEWEX
projects. • CLIVAR and GEWEX should organise further pan WCRP workshops
building on the progress of the first pan WCRP Monsoon Workshop.
• The JSC group responsible for further oversight of Monsoons is G. Wu (Chair), J. Slingo, T.
Yasunari, C. Vera, L. A.. Ogallo and J. Shukla.
Decision:
Endorse the WCRP crosscutting Monsoon Initiative. The JSC
commented that the monsoon crosscut should include all the monsoon
groups with a broader perspective, led by CLIVAR and GEWEX with
participation of SPARC, CliC and WGNE and several activities outside
WCRP (particularly THORPEX).
Request CLIVAR and GEWEX to agree on how it will be supervised
and the development of an implementation plan. The proposals for and
concepts of an Asian Monsoon Year and an International Year of
Tropical Convection should be considered as components of an
International Monsoon Study 2007-2011, a 5-year strategy of WCRP
monsoon research, which would include issues related to the East
African Monsoon, capacity building and application of observations
and predictions in monsoon regions for societal benefit. GEWEX and
CLIVAR to rationalise the number of monsoon committees.
““Asian Monsoon Year (AMY’08)”:Asian Monsoon Year (AMY’08)”:The “Asian Monsoon Year (AMY08)” (2008-The “Asian Monsoon Year (AMY08)” (2008-2009) initiative is 2009) initiative is a coordinated observation a coordinated observation and modeling effort on understanding the and modeling effort on understanding the aerosol-cloud/radiation--hydrology cycle-aerosol-cloud/radiation--hydrology cycle-circulation interaction and ocean-land-circulation interaction and ocean-land-atmosphere interaction of the Asian atmosphere interaction of the Asian monsoon system, and on improving monsoon system, and on improving monsoon prediction. monsoon prediction.
2. Energy and water cycle
62444
20
10 1 5 4
Global mean
Downward net Radiation
Latent heat release
Sensible heat release
Longwave radiation
Energy Budget at the surface
Water cycle over SCS
May-Jun. (105- 120E, 0- 20N ); 1.0106 kg s-1.
JUN
385.9
PRCP 165.4
63.8
149.4
160.6
46.0
MAY
136.1
EVAP98.6
PRCP
266.4
63.8
204.0
97.3
JUNE
165.4
EVAP385.9
PRCP
334.7
PRCP 165.4
63.8
28.1
219.8
46.0
JULY
163.6
EVAP335.1
PRCP
336.6
165.2
124.3
128.6
AUG.
170.3
EVAP397.6
PRCP
372.6
Water cycle over SCS
Jul-Aug. (105- 120E, 0- 20N ); 1.0106 kg s-1.
Total Precipitation P= Po+ Pi
Recyc. Prec. Ratio R=Pi/P
Evaporation and rainfall
Vq Vq
Po Pi E
““Asian Monsoon Year (AMY’08)”:Asian Monsoon Year (AMY’08)”:The “Asian Monsoon Year (AMY08)” (2008-The “Asian Monsoon Year (AMY08)” (2008-2009) initiative is 2009) initiative is a coordinated observation a coordinated observation and modeling effort on understanding the and modeling effort on understanding the aerosol-cloud/radiation--hydrology cycle-aerosol-cloud/radiation--hydrology cycle-circulation interaction and ocean-land-circulation interaction and ocean-land-atmosphere interaction of the Asian atmosphere interaction of the Asian monsoon system, and on improving monsoon system, and on improving monsoon prediction. monsoon prediction.
3. Land-air-sea interaction
b
150
50
180
100
30
-220
-240
L S C
a
D
L S C D
c
Kd-1
L S C D
Summertime quadruplet heating LOSECOD
Circulation exited by
LOSECOD
1 v ( )( / )z f Q z
AAEAPNAA
b
c
d
AAEAPNAA
a
Subtropical LOSECOD
Heating and anticyclone1 v ( )( / )z f Q z
PSAm
ASAf IAU
b
c
d
a
PSAm ASAf IAU
Subtropical LOSECOD
Heating and anticyclone1 v ( )( / )z f Q z
Western PacificWestern Pacific Subtropical anticycloneSubtropical anticyclone
Sub. HighSub. HighRain
台风路径的合成差分布(暖年-冷年, 7 - 10月)
Western Pacific SSTa and Typhone tract
Ocean thermal stateOcean thermal state
Transfer of watervaperTransfer of watervaper
evaporationevaporation
索马里急流
水 汽水 汽
海 面 海 面
蒸 发蒸 发
Indian Ocean
季风低压
DD
索马里急流
马斯克林高压
Monsoon=>ocean current=>SST -- QBO,
MISO
图5.24a
图5.27a
“ Two-stage thermal adaptation” of theatmospheric circulation to the SSTA in thenorthern Indian Ocean
孟加拉湾SSTA激发西太平洋副高异常的“ 两级热力适应”的概念模型
850hPa
1000hPa
+SSTA
850hPa
1000hPa
+SSTA
200hPa
500hPa
A
A
a) b)
During northern summer, the oceanic TCZ migrates seasonally over Indian sub-continent
and leads to formation of a semi-permanent system known as monsoon trough (CTCZ) by second fortnight of July.
The monsoon trough is controlled by two centers of lows
Seasonal low At western end over Pakistan and adjoining area
Transient disturbances Form over the Head Bay
region and move across the trough.
frequency distribution of SAH center (NCEP/NCAR pentad mean)
Modulation of the Tibetan Plateau
The composed 100hPa streamlines and vectors in Jul-Aug
the composed surface temperature anomalies
composed precipitation for Tibetan High in Jul-Aug (mm/5day)
Coupling of air-sea interaction between
tropical Pacific and Indian Ocean
LA
TIT
UD
E
(a)
LA
TIT
UD
E
(c)
SS
T A
NO
MA
LY
(b)
图 1
赤道太平洋 - 印度洋海气相互作用的耦合示意图
Affect: interannual variability and MISO=>Active
and break of monsoon
Indian Ocean Pacific Ocean
upweling upwelling
太平洋
Warm Warm
waterwater
Atmos Atmos
circulationcirculation
Atmos Atmos
circulationcirculation
Our shortcomings in tropical convection severely limit Our shortcomings in tropical convection severely limit the representation of key physics in weather & climate the representation of key physics in weather & climate modelsmodels
• Diurnal cycle - strongest “forced” signal in the climate system.
• Synoptic waves and easterly waves, including development & evolution of hurricanes and Tropical cyclones
• Madden-Julian Oscillation (MJO) and other large-scale convectively-coupled waves
• monsoon variability, including onset and break activity.
• Tropical mean state, including ITCZ and distributions of rainfall over oceans & continents
Winter 2005-6
Kelvin WavesKelvin Waves
Rossby WavesRossby Waves
MJOs
Dominant Convectively-Coupled Tropical Waves Projected onto OLR Anomalies. Wheeler and Weickmann, 2001
SAM
EAMAM
WP Flow 台风源区台风源区
Three monsoon systems interact
Typhoons invade
The monsoon moisture fluxThe monsoon moisture flux
Persistent
anomaly
Sudden
flood
4. Science Issues
The regional perspective
strengthening coordination of Asian-Australian monsoon research:
The air-sea interaction over The air-sea interaction over Indian OceanIndian Ocean and its impacts on Asian monsoon and its impacts on Asian monsoon
variability (MISO, seasonal and interannual);variability (MISO, seasonal and interannual);
Land-sea thermal contrast, diurnal cycle and CTCZ/OTCZ;
Modulation of the TP energy and water cycle on the air-sea interaction over
N Indian Ocean;
Air-sea interaction over Air-sea interaction over Western PacificWestern Pacific and its impacts on subtropical anticyclone; and its impacts on subtropical anticyclone;
The impacts on Asian monsoon of the air-sea coupling process between The impacts on Asian monsoon of the air-sea coupling process between tropical tropical
Pacific and Indian Ocean;Pacific and Indian Ocean;
Water cycleWater cycle and its variation over the Asian monsoon areas and its variation over the Asian monsoon areas
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