Multi-Scale Forcing and Formation of Desert and Monsoon PAGES 2 nd Global Monsoon Symposium, Shanghai, Sep , 2010 Guoxiong Wu Yimin LIU, Anmin Duan, and Xiaoyun Liang State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics (IAP) Chinese Academy of Sciences (CAS), Beijing Guoxiong Wu Yimin LIU, Anmin Duan, and Xiaoyun Liang State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics (IAP) Chinese Academy of Sciences (CAS), Beijing

Ann. Geophys., 27, 1–14, Annales Geophysicae // keywords.pdf Multi-scale forcing and the formation of subtropical desert and monsoon G. X. Wu, Y. Liu, X. Zhu, W. Li, R. Ren, A. Duan, and X. Liang Correspondence to: Y. Liu

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 Adaptation 1 Continental Scale “LOSECOD” Heating 2 Local Scale Forcing-Dry and Wet Climate 3 Tibetan Plateau Regional Scale Forcing 4 Formation of Desert and Monsoon 5 6 Summary LIST

Vorticity Equ. steady Subtro. ： W determined by the vertical shear of v Thermal adaptation- heat source LOSECOD Quadruplet Heating HEATING A C

COOLING C A Thermal adaptation- heat sink LOSECOD Quadruplet Heating

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

Thermal Adaptation 1 Continental Scale “LOSECOD” Heating 2 Local Scale Forcing –Sea breeze 3 Tibetan Plateau Regional Scale Forcing 4 Formation of Desert and Monsoon 5 6 Summary LIST

1000 hPa velocity potential (shaded ) in unit of 10 6 m 2 /s and divergent wind component (arrow) in unit of m/s ( ) Jan. July a)

Thermal Adaptation 1 Continental Scale “LOSECOD” Heating 2 Local Scale Forcing-Dry and Wet Climate 3 Tibetan Plateau Regional Scale Forcing 4 Formation of Desert and Monsoon 5 6 Summary LIST

LO SE D CO LOSE CO SE CO N.Pacific-O N.Atlan-O LOD D

Vertical-integrated dominant heating “ LOSECOD ” quadruplet heating D LO SH CO D LOSECOD Quadruplet Heating Longwave Rad cooling Longwave SensibleHeatingSensibleHeating CondensationHeatingCondensationHeating Double Dominant Heating Heating

σ σ a) b) LOSECOD LOSECOD Kd -1 Eurasian Continent / 欧亚大陆 N. America / 北美大陆

10mm d -1 ~2.5*10 -5 Ks -1, maximum heating layer Z M ~ mb, Q~ Ks -1 for z Z M Northerlies are forced above Z M ; southerlies are forced below Z M. Thermal Adaptation - Sverdrup balance Why?

Fig. 10 (a) SENSIBLE HEATING 30 o N CONTINENT 30 o N OCEAN (b) LATENT HEATING 30 o N CONTINENT 30 o N OCEAN (c) RADIATION COOLING 30 o N CONTINENT 30 o N OCEAN S C L

a) c) b b) D CO SE LO SELO COD LOSECOD

a) c) b) LOSECOD

Positive Feedback Mechanism heating ＝》 vor. generation ＝》 v develops ＝》 further heating N E Z N E Z W. continent- SE E. continent- CO VOR. HEATING

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

Thermal Adaptation 1 Continental Scale “LOSECOD” Heating 2 Local Scale Forcing-Dry and Wet Climate 3 Tibetan Plateau Regional Scale Forcing 4 Formation of Desert and Monsoon 5 6 Summary LIST

青藏高原对夏季季风降水的影响

Thermal Adaptation- heating heating

气压 (hPa) 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  - 30 o N + W

Thermal Adaptation 1 Continental Scale “LOSECOD” Heating 2 Local Scale Forcing-Dry and Wet Climate 3 Tibetan Plateau Regional Scale Forcing 4 Formation of Desert and Monsoon 5 6 Summary LIST

Desert and monsoon along the subtropics are therefore formed!

Thermal Adaptation 1 Continental Scale “LOSECOD” Heating 2 Local Scale Forcing-Dry and Wet Climate 3 Tibetan Plateau Regional Scale Forcing 4 Formation of Desert and Monsoon 5 6 Summary LIST

Summary Desert and Monsoon are formed as a twin system due to the atmospheric thermal adaptation to multi-scale forcing, including: Desert and Monsoon are formed as a twin system due to the atmospheric thermal adaptation to multi-scale forcing, including: Continental Scale forcing- “LOSECOD”;Continental Scale forcing- “LOSECOD”; Local Scale Forcing- Sea- breeze; andLocal Scale Forcing- Sea- breeze; and Regional scale forcing- OrographyRegional scale forcing- OrographySummary Desert and Monsoon are formed as a twin system due to the atmospheric thermal adaptation to multi-scale forcing, including: Desert and Monsoon are formed as a twin system due to the atmospheric thermal adaptation to multi-scale forcing, including: Continental Scale forcing- “LOSECOD”;Continental Scale forcing- “LOSECOD”; Local Scale Forcing- Sea- breeze; andLocal Scale Forcing- Sea- breeze; and Regional scale forcing- OrographyRegional scale 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: /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 YIMIN LIU, GUOXIONG WU, AND RONGCAI REN, 2004: Relationship between the Subtropical Anticyclone and Diabatic Heating. J. Climate, 2004, 17: Wu, Guoxiong, Yimin Liu, and Png Liu, 2004: Formation of the summertime subtropical anticyclone. East Asian Monsoon, Edited by C. P. Chang.World Scientific 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: /2004GL 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: 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.

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