multi-scale forcing and formation of desert and monsoon pages 2 nd global monsoon symposium,...

Multi-Scale Forcing and Formation Multi-Scale Forcing and Formation of Desert and Monsoonof Desert and Monsoon

Multi-Scale Forcing and Formation Multi-Scale Forcing and Formation of Desert and Monsoonof Desert and Monsoon

PAGES 2nd Global Monsoon Symposium, Shanghai, Sep. 13-15, 2010

Guoxiong WuGuoxiong Wu

Yimin LIU, Anmin Duan, and Xiaoyun LiangYimin LIU, Anmin Duan, and Xiaoyun Liang

State Key Laboratory of Numerical Modeling for State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Atmospheric Sciences and Geophysical Fluid

Dynamics (Dynamics (LASGLASG))Institute of Atmospheric Physics (Institute of Atmospheric Physics (IAPIAP))

Chinese Academy of Sciences (Chinese Academy of Sciences (CASCAS), Beijing), Beijing

Guoxiong WuGuoxiong Wu

Yimin LIU, Anmin Duan, and Xiaoyun LiangYimin LIU, Anmin Duan, and Xiaoyun Liang

State Key Laboratory of Numerical Modeling for State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Atmospheric Sciences and Geophysical Fluid

Dynamics (Dynamics (LASGLASG))Institute of Atmospheric Physics (Institute of Atmospheric Physics (IAPIAP))

Chinese Academy of Sciences (Chinese Academy of Sciences (CASCAS), Beijing), Beijing

Ann. Geophys., 27, 1–14, 2009www.ann-geophys.net/27/1/2009/

Annales Geophysicae //www.annales-geophysicae.net/angeo keywords.pdf

Multi-scale forcing and the formation of subtropical desert and monsoonG. X. Wu, Y. Liu, X. Zhu, W. Li, R. Ren, A. Duan, and X. Liang

Correspondence to: Y. Liu ([email protected])

mailto:[email protected]

Theories on the formation of deserts

1.Tradition— The descending arm of the Hadley Circulation

2. Charney— Bio-Geo local positive feedback

3. Rodwell & Hoskins— Monsoon Remote driven

4. Our view —Monsoon and Desert Coexist as a twin system

due to concurrent multi-scale forcing

Thermal AdaptationThermal Adaptation1

Continental Scale “LOSECOD” HeatingContinental Scale “LOSECOD” Heating

2 Local Scale Forcing-Dry and Wet ClimateLocal Scale Forcing-Dry and Wet Climate

3

Tibetan Plateau Regional Scale ForcingTibetan Plateau Regional Scale Forcing4

Formation of Desert and MonsoonFormation of Desert and Monsoon5

6 SummarySummary

LISTLIST

E

N

Z

Vorticity Equ.z

wfv

yv

xu

t

)(

steady

steady

Subtro.：Subtro.： ,0u .0/ y

z

wfv

z

v

fw

W determined by the W determined by the

vertical shear of vvertical shear of vW determined by the W determined by the

vertical shear of vvertical shear of v

Thermal adaptation- heat Thermal adaptation- heat sourcesource

LOSECOD Quadruplet Heating

HEATING

A

C

COOLING

C

A

E

N

Z

z

v

fw

Thermal adaptation- heat Thermal adaptation- heat sinksink


Winter:

Source-ocean; sink-land

Summer:

Source-land; sink-ocean

北美大陆欧亚大陆

Asymmetry: Eastern Ascent/descent stronger than the western one

N. Amer. EurAsia

A

C

C

A

A

C

C

A

C

A



2 Local Scale Forcing –Sea breezeLocal Scale Forcing –Sea breeze

3



6 SummarySummary

LISTLIST

1000 hPa velocity potential (shaded ) in unit of 106 m2/s and divergent

wind component (arrow) in unit of m/s (1980-1997)

Jan.

July

a)




3



6 SummarySummary

LISTLIST

LO

.0

;00

0

QV

g

dpQ

p

SE

.0

;00

0

QV

g

dpQ

p

D

.0

;00

0

QV

g

dpQ

p

CO

.0

;00

0

QV

g

dpQ

p

LO SE CO SE CO

N.Pacific-ON.Atlan-O

LO DD

Vertical-integrated dominant heating “LOSECOD” quadruplet heating

LO SH CO DD


LongwaveLongwave

Rad coolingRad cooling

LongwaveLongwave

Rad coolingRad cooling

SensibleSensible

HeatingHeating

SensibleSensible

HeatingHeating

CondensationCondensation

HeatingHeating

CondensationCondensation

HeatingHeating

Double DominantDouble Dominant

HeatingHeating

Double DominantDouble Dominant

HeatingHeating

σ

σ

a)

b)

LO SE CO D

LO SE CO D

Kd-1

Eurasian Continent / 欧亚大陆

N. America / 北美大陆

10-11-

zzz

10 10

QfVfvVt )0(,)()(/ 1

10mm d-1~2.5*10-5 Ks-1, maximum heating layer ZM~300-400mb,

Q~ 10-4 Ks-1 for z< ZM, but 10-5 Ks-1 for z> ZM

).0()(0

)(0)(11

z

M

Mzz Zz

ZzQf

Northerlies are forced above ZM; southerlies are forced below ZM.

Thermal Adaptation

- Sverdrup balance

1( ) , ( 0)z z zv f Q

Why?

a)

c)

bb)

DCOSELO SELO CO D

LOSECOD

a)

c)

b)

LOSECOD

Positive Feedback Mechanismheating ＝》 vor. generation ＝》 v develops ＝》 further heating

N

E

Z

N

E

Z

W. continent-

SEE. continent-

CO

z

Q

v Qv

y

VOR. HEATING

Desert/dry climate is formed over the western continents, whereas monsoon/wet climate is formed over the eastern continents!




3



6 SummarySummary

LISTLIST

青藏高原对夏季季风降水的影响

C

A

Thermal Adaptation- heating

E

N

Z

v

zw

heating

气压

(h

Pa)

气压

(h

Pa)

Tibetan July

Rockies July

Andes January

v

++-

- ++-

-

+-

-

-

July Monsoon/desert Experiment ７月季风降水敏感试验

a) Without mountain

b) With mountain

b) –a)

a) 60E mountain

b) 90E mountain

July Monsoon/desert Experiment ７月季风降水敏感试验

a)

f)

b) e)

d)

c)

V-850mb+R

V-200mb+R

-30oN + W




3



6 SummarySummary

LISTLIST

Desert and monsoon along the Desert and monsoon along the

subtropics are therefore formed!subtropics are therefore formed!




3



6 SummarySummary

LISTLIST

SummarySummary

Desert and Monsoon are formed as a twin Desert and Monsoon are formed as a twin systemsystem due to the atmospheric thermal due to the atmospheric thermal adaptation to multi-scale forcing, including:adaptation to multi-scale forcing, including:

•Continental ScaleContinental Scale forcing- forcing-

“LOSECOD”;“LOSECOD”;

•Local ScaleLocal Scale Forcing- Sea- breeze; and Forcing- Sea- breeze; and

•Regional scaleRegional scale forcing- Orography forcing- Orography

SummarySummary

Desert and Monsoon are formed as a twin Desert and Monsoon are formed as a twin systemsystem due to the atmospheric thermal due to the atmospheric thermal adaptation to multi-scale forcing, including:adaptation to multi-scale forcing, including:

•Continental ScaleContinental Scale forcing- forcing-

“LOSECOD”;“LOSECOD”;

•Local ScaleLocal Scale Forcing- Sea- breeze; and Forcing- Sea- breeze; and

•Regional scaleRegional scale forcing- Orography forcing- Orography

Related Publications

•Wu, Guoxiong and Yimin Liu, 2003: Summertime quadruplet heating pattern in the subtropics and the associated atmospheric circulation. Geophys. Res. Lett., 30(5), 1201, doi:10.1029/2002GL016209, 5_1-4

•Wu, Guoxiong, Yimin Liu, Jianyu Mao, Xin Liu And Weiping Li. 2004: Adaptation of the atmospheric circulation to thermal forcing over the tibetan plateau. Obseervation, Theory And Modeling Of The Atmospheric Variability. Selected Papers Of Nanjing Institute Of Mateorology Alumni In Commemoration Of Professor Jijia

Zhang, Edited By Xun Zhu Etc.World Scientific 92-114.

•YIMIN LIU, GUOXIONG WU, AND RONGCAI REN, 2004: Relationship between the Subtropical

Anticyclone and Diabatic Heating. J. Climate, 2004, 17: 682-698.

•Wu, Guoxiong, Yimin Liu, and Png Liu, 2004: Formation of the summertime subtropical anticyclone. East

Asian Monsoon, Edited by C. P. Chang.World Scientific 499-544. •Xiaoyun Liang, Yimin Liu, and Guoxiong Wu , 2005: The role of land-sea distribution in the formation of ★

the Asian summer monsoon. Geoph. Res. Lett. 32: 10.1029/2004GL021587 •Guoxiong Wu, Yimin Liu, Tongmei Wang, Rijin Wan, …,2007: The Influence of the Mechanical and

Thermal Forcing of the Tibetan Plateau on the Asian Climate. J. Hydrometeorology. 8: 770-789. •WU Guoxiong1, LIU Yimin1,*, YU Jingjing1,2, ZHU Xiaying1,2 and REN Rongcai ： Modulation of

Land-Sea Distribution on Air-Sea Interaction and Formation of Subtropical Anticyclones ， To appear in Chinese JAS.

Thank Thank You!You!Thank Thank You!You!

multi-scale forcing and formation of desert and monsoon pages 2 nd global monsoon symposium,...

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