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