Multiscale forcing and the change of East Asia monsoon Yimin LIU, Guoxiong Wu, Anmin Duan, Xiaoyun Liang and Rijun Wan LASG, Institute of Atmospheric Physics (IAP) Chinese Academy of Sciences (CAS), Beijing Buwen Dong Department of the Meteorology, University of Reading Reading UK ， July 28-30, 2008

Surface T trend Rainfall Trend Xu and Chang et al., trend for JJA

LIST 1. Thermal Adaptation 2. Land Distribution and Continental Scale “LOSECOD” Heating 3. Tibetan Plateau Local Scale Forcing 4. Climate changes over the TP and its impacts 5. Summary

Thermal Adaptation- heating heating

Thermal Adaptation-cooling cooling

Winter: Source-ocean; sink-land Summer: Source-land; sink-ocean

Atmospheric adaptation to summertime continental scale forcing results in ascent over eastern-continent/western-ocean but descent over eastern-ocean/western-continent; However, the atmospheric response is asymmetric: eastern signals are always stronger than the western signals

LIST 1. Thermal Adaptation 2. Land Distribution and Continental Scale “LOSECOD” Heating 3. Tibetan Plateau Local Scale Forcing 4. Climate changes over the TP and its impacts 5. Summary

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

Eurasian-C N.Pacific-O N.Amer-C N.Atlan-O 图 1.5 LOSE COD LOSE CODLO SECO D

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

AAEA PNAA b c d AAEA PNAA a LOSECOD Total vertical column heating Main heating V and H* at 100hPa V and H* at 1000hPa

PSAm ASAf IAU b c d a PSAm ASAf IAU LOSECOD Total vertical column heating Main heating V and H* at 100hPa V and H* at 1000hPa

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

LIST 1. Thermal Adaptation 2. Land Distribution and Continental Scale “LOSECOD” Heating 3. Tibetan Plateau Local Scale Forcing 4. Climate changes over the TP and its impacts 5. Summary

Thermal Adaptation- heating heating

气压 (hPa) Tibetan July Rockies July Andes January  v

a) Without mountain b) With mountain b) –a) July Monsoon Experiment, Pre (shaded) and v850

a) 60E mountain b) 90E mountain July Monsoon Experiment, Pre (shaded) and v850

LIST 1. Thermal Adaptation 2. Land Distribution and Continental Scale “LOSECOD” Heating 3. Tibetan Plateau Local Scale Forcing 4. Climate changes over the TP and its impacts 5. Summary

Data: Station observations: 1. 64/71 surface stations in Central and Eastern Tibetan Plateau (CE- TP) during ; 2.9/12 radiosonde stations in CE-TP during / Reanalysis: 1.ERA40 Reanalysis data during ; 2.NCEP/R1 Reanalysis data during Total ozone amount: NASA Goddard Space Flight Center (GSFC) ( during with a horizontal resolution of 5° latitude and 10° longitude.

Chen et al., (2003); Du (2001;2004); Liu et al., (2000;2001;2006); Niu et al., (2004); Zhu et al., (2001); … Previous Study review: The Tibetan Plateau is one of the most significant warming area in the world Glacier retreat in Meli Jokul (98.1E, 28.06N)

Strong surface warming and diminished DTR Linear variation rate （ LVA ） of the annual mean surface air temperature (a) and its diurnal range (DTR) (b) during in units of ℃ /decade. Triangles, open circles, and solid circles denote stations above 4000, 3000, and 2000 m, respectively.

Tave RainTmin Tmax 64 station-averaged Linear trend During 1961 － 2003, the 64-station-averaged LVR of the annual mean Tmin (0.57 ℃ /10a) is twice larger than that of the Tmax (0.27 ℃ /decade). Strong surface warming and diminished DTR

Differences of Ta anomalies among observation, ERA40, and NCEP/R1 Comparison between observation and reanalysis (a) The CE-TP area; (b) Northern subtropics and Northern Hemisphere. Red, blue, and yellow curves are observed, ERA40-, and NCEP-based temperature anomalies, and the green curve denotes the observed DTR over the CE-TP; Purple and cyan curves in (b) denote the ERA40-based temperature anomalies over the Northern Subtropics and the Northern Hemisphere, respectively. Solid and dotted lines represent the linear trends and the chief abrupt change points of the curves with the same colour. CE-TP NS and NH ERA40 Observ NCEP

Relative change rate (RCR) in percentage of the surface air temperature (a-c), total cloud amount (d-f), and low-level cloud amount (g-i) in the period of (a), (d), and (g) for 0600 LT, (b), (e), and (h) for 1200 LT, and (c), (f), and (i) represent the difference between 0600 LT and 1200 LT LST LST Surface air Temp LST Low cloud amount Total cloud amount Warming and diminished DTR related cloud change

NumberStation IDStation nameFirst yearLatitude, NLongitude, EElevation (m) Mangai  15'90  51' *Geermu  25'94  54' Dulan  18'98  06' *Xining  43'101  45' *Naqu  29'92  04' *Lhasa  40'91  08' *Yushu  01'97  01' Dari  45'99  39' *Changdu  09'97  10' 3306 Temporal evolutions of the standardized 9 station averaged air temperature at 150 hPa (red) and 50 hPa (green) Change in upper layers Temporal evolutions of the ERA40 standardized air temperature at 150 hPa (Solid) and 50 hPa (dashed). Observation ERA

Change in in upper atmosphere Time-altitude sections of the linear trends for (a) air temperature (in unit of ℃ ·decade-1), (b) geopotential height (in unit of dagpm·decade-1), and (c) wind speed (in unit of m s-1·decade-1) as averaged from the 12 radiosonde stations over the TP during the period Ta GPH V

Temperature anomaly in upper layers for 20C3m and PICNTRL MIROC_3.2GFDL_CM hPa 50hPa Numerical Simulation The standardized surface layer temperature and DTR anomalies over the CE-TP (85-105ºE; ºN) MIROC_3.2GFDL_CM2.1 PICNTRL 20C3M Observed change in TP can only be reproduced in 20C3m scenario by two models

Temporal evolution of Ta (a and b), Ts (c and d), V0 (e and f), and SH (g and h) in the CE-TP at 0000 LST/DJF (left panels) and 1200 LST/MAM (right panels). The units of Ta and Ts are ℃, V0 m·s-1, and SH W·m-2. Curves with open circles are 71-station-averaged and closed circles are 37-station-averaged. V10 Ts Ta SH Decreased sensible heat flux over TP

Slightly increased latent heat flux over TP Temporal evolution (upper panel, in units of W·m-2) and spatial distribution (lower panel, in units of W·m-2·decade-1) of the LVR of LH in four seasons over CE-TP during

Sensitivity experiments by HadAM3 JJA Difference between less and more albedo over the TP Ts Ta SHv850

Sensitivity experiments by Had3 JJA Pre. In CON Run Pre. diff. between less and more TP albedo

Wang et al, 2008

Surface T trend Rainfall Trend Xu and Chang et al., 2006

LIST 1. Thermal Adaptation 2. Land Distribution and Continental Scale “LOSECOD” Heating 3. Tibetan Plateau Local Scale Forcing 4. Climate changes over the TP and its impacts 5. Summary

Summary Asian Monsoon are formed due to the atmospheric thermal adaptation to Continental Scale “LOSECOD” forcing and certain kind of Local Scale Forcing

 , a striking climate warming is accompanied by the decreasing trends of the surface DTR;  The change of cloud amount seems to be directly related to this change;  Simulation results of two IPCC models suggest that, the recent climate warming over TP may be closely connected with the anthropogenic GHGs emissions;  , Ts and Ta over the TP both get warmer, with the latter stronger than the former; V10 gets weaker  Surface sensible heating is reduced;  Radiation cooling increased, not much change in latent heating  TP thermal forcing is reduced;  Weekend TP thermal forcing contributes to the dry of Northern China. Summary for climate change over the TP

Thank You!

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.

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

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

Annual mean time series at Golmud for years (a) surface air temperature,(b) DTR, (c) low-level cloud amount, (d) total cloud amount, (e) horizontal direct radiation flux, (f) diffuse radiation flux, and (g) global radiation flux. Temperature and DTR are in units of oC. Cloud amount varies from 0 to 10 tenths of sky cover. Units of radiation flux are 10e6 J m-2. Ta DTR Low cloud Total cloud Horizontal direct solar radiation flux Diffuse solar radiation flux Global solar radiation flux Warming and diminished DTR related cloud change: A case study at Golmud