The Dipole Mode of the Summer Rainfall over East China during 1958–2001  

作　　者：韩晋平 张人禾 

机构地区：[1]State Key Laboratory of Severe Weather(LaSW), Chinese Academy of Meteorological Sciences [2]Nansen-Zhu International Research Centre,Institute of Atmospheric Physics, Chinese Academy of Sciences

出　　处：《Advances in Atmospheric Sciences》2009年第4期727-735,共9页大气科学进展（英文版）

基　　金：supported by the National Basic Research Program of China(Grant Nos 2004CB418302 and 2009CB421404);Na-tional Natural Science Foundation of China (Grant No40675058)

摘　　要：By examining the second leading mode （EOF2） of the summer rainfall in China during 1958 2001 and associated circulations, the authors found that this prominent mode was a dipole pattern with rainfall decreasing to the north of the Yangtze River and increasing to the south. This reverse relationship of the rainfalls to the north and to the south of the Yangtze River was related with the meridional circulations within East Asia and the neighboring region, excited by SST in the South China Sea-northwestern Pacific. When the SST was warmer, the geopotential heights at 500 hPa were positive in the low and high latitudes and negative in the middle latitudes. The anticyclone in the low latitudes favored the subtropical high over the northwestern Pacific （SHNP） shifting southwestward, leading to additional moisture transport over southern China. The anomalous atmospheric circulations along the East Asian coast tends to enhance upward movement over the region. Subsequently, rainfall in southern China is enhanced.By examining the second leading mode （EOF2） of the summer rainfall in China during 1958 2001 and associated circulations, the authors found that this prominent mode was a dipole pattern with rainfall decreasing to the north of the Yangtze River and increasing to the south. This reverse relationship of the rainfalls to the north and to the south of the Yangtze River was related with the meridional circulations within East Asia and the neighboring region, excited by SST in the South China Sea-northwestern Pacific. When the SST was warmer, the geopotential heights at 500 hPa were positive in the low and high latitudes and negative in the middle latitudes. The anticyclone in the low latitudes favored the subtropical high over the northwestern Pacific （SHNP） shifting southwestward, leading to additional moisture transport over southern China. The anomalous atmospheric circulations along the East Asian coast tends to enhance upward movement over the region. Subsequently, rainfall in southern China is enhanced.

关 键 词：second leading mode RAINFALL dipole pattern sea surface temperature 

分 类 号：P426.61[天文地球—大气科学及气象学]