250 Science in China Ser. D Earth Sciences 2005 Vol.48 No.2 250 257 Copyright by Science in China Press 2005 Heating status of the Tibetan Plateau from April to June and rainfall and atmospheric circulation anomaly over East Asia in midsummer DUAN Anmin, LIU Yimin & WU Guoxiong State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China Correspondence should be addressed to Duan Anmin (email: amduan@mail.iap.ac.cn ) Received November 15, 2002; revised January 20, 2003 Abstract Based on the 1958—1999 monthly averaged reanalysis data of the National Center for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) and the rainfall data of 160 Chinese surface stations, the relationship between rainfall and the atmos- pheric circulation anomaly over East Asia (EA) in July and the sensible heating (SH) over the Tibetan Plateau (TP) from April to June (AMJ) is investigated by using the rotational experimental orthogonal function (REOF) method. The results show that the TP is an isolated heating source in this period. The lagged correlation analysis between the first rotational principal component (RPC) of SH over the TP in May and rainfall of EA in July demonstrates that strong SH over the TP before July leads to a positive rainfall anomaly over the TP, the valley between the Yangtze River and Huaihe River, and the regions south and southeast of the TP, and the Sichuan Basin and Yunnan-Guizhou Plateau, but less rainfall anomaly over the regions north, northeast, and west of the TP. Such rainfall anomaly patterns are shown to be well coordinated with those of the circulation and vapor flux fields, and are explained by using the thermal adaptation theory and quasi-stationary large-scale vorticity equation. Therefore, the status of SH over the TP during AMJ can be used as a predictor for the rainfall anomaly over EA, especially in the valley between the Yangtze River and Huaihe River. Keywords: Tibetan Plateau, sensible heating, East Asia, rainfall, circulation. DOI: 10.1360/02yd0510 It is well known that the mechanical and thermal forcing of the TP influences the atmospheric circula- tion, weather, and climate of the Northern Hemisphere remarkably. As early as in the 1950s, Yeh [1] found that the seasonal transition over EA happens abruptly and is associated with the existence of the TP. Later, Yeh et al. [2] and Flohn [3] found that the air column over the TP is a heat source in summer. By analyzing the variation characteristics of the South Asia High, Flohn [4] brought forward a viewpoint that the South Asia High is a consequence of the thermal forcing of the TP. Furthermore, the results of numerical experiments by Broccoli and Manabe [5] showed that large-scale oro- graphy such as the TP and Rocky Mountains can result in the drought climate in the middle latitude belt over the Northern Hemisphere. Wu and Zhang [6] analyzed the relation of the persistent land SH over the TP to the Asia summer monsoon onset and pointed out that due to the strong advection in spring, such a persistent SH leads to warmer air temperatures over the eastern TP, to the development of the lower layer southerly to the area, and convergence there. This then provides a fa-