印度洋海温偶极振荡对东亚环流及降水影响

Effect of IOD on East Asian Circulation and Precipitation

利用NCEP/NCAR提供的50a再分析资料、英国气象局全球海温资料、中国气象局整编的160站降水资料,采用相关、合成、奇异值分解等方法讨论了印度洋海温异常偶极振荡对东亚夏季大气环流及降水的影响。结果表明:印度洋海温偶极振荡异常,引起了大气环流的异常,影响了季风强度和雨带分布。印度洋海温偶极振荡正位相年时,印度洋上为东风异常,西太平洋副高偏西、偏南、偏强,菲律宾附近对流活动减弱,东亚夏季风偏强,华南夏季降水偏多;印度洋海温偶极振荡负位相年时,西太平洋副高偏东、偏北,东亚夏季风偏弱,长江黄河之间有异常辐合,降水偏多。

Based on the U.K.global SST,NCEP/NCAR reanalysis data and 160 stations rainfall data in China,by using the composite and singular value decomposition(SVD) methods,the effect of the Indian Ocean Dipole(IOD) on East Asian atmospheric circulation and precipitation in 1951-2000 has been studied in the present article.Results show that the IOD anomaly results in anomalous atmospheric circulation,which affects the distribution of the rain belt during rainy seasons in China and the East Asian monsoon.When the IOD is positive(negative),the subtropical high is south(north),and west(east) of its mean position,and stronger(weaker) than normal;the East Asian monsoon is stronger(weaker);the summer rainfall is less(more) in the Yangtze River basin and more(less) in south China.