Contrasts between the Interannual Variations of Extreme Rainfall over Western and Eastern Sichuan in Mid-summer  

作　　者：Mengyu DENG Riyu LU Chaofan LI 

机构地区：[1]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [2]Center for Monsoon System Research,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [3]College of Earth and Planetary Sciences,University of the Chinese Academy of Sciences,Beijing 100049,China [4]Institute of Plateau Meteorology,China Meteorological Administration(CMA),Chengdu 610072,China [5]Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province,Chengdu 610072,China

出　　处：《Advances in Atmospheric Sciences》2022年第6期999-1011,共13页大气科学进展（英文版）

基　　金：supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA23090102);the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(Grant No.2019QZKK0102).

摘　　要：Rainfall amount in mid-summer(July and August)is much greater over eastern than western Sichuan,which are characterized by basin and plateau,respectively.It is shown that the interannual variations of extreme rainfall over these two regions are roughly independent,and they correspond to distinct anomalies of both large-scale circulation and sea surface temperature(SST).The enhanced extreme rainfall over western Sichuan is associated with a southward shift of the Asian westerly jet,while the enhanced extreme rainfall over eastern Sichuan is associated with an anticyclonic anomaly in the upper troposphere over China.At low levels,on the other hand,the enhanced extreme rainfall over western Sichuan is related to two components of wind anomalies,namely southwesterly over southwestern Sichuan and northeasterly over northeastern Sichuan,which favor more rainfall under the effects of the topography.Relatively speaking,the enhanced extreme rainfall over eastern Sichuan corresponds to the low-level southerly anomalies to the east of Sichuan,which curve into northeasterly anomalies over the basin when they encounter the mountains to the north of the basin.Therefore,it can be concluded that the topography in and around Sichuan plays a crucial role in inducing extreme rainfall both over western and eastern Sichuan.Finally,the enhanced extreme rainfall in western and eastern Sichuan is related to warmer SSTs in the Maritime Continent and cooler SSTs in the equatorial central Pacific,respectively.

关 键 词：extreme rainfall SICHUAN interannual variation TOPOGRAPHY large-scale circulation 

分 类 号：P426.614[天文地球—大气科学及气象学]