夏季西太平洋暖池海温的年际变化特征及其影响分析

Interannual Variation Characteristics of the Western Pacific Warm Pool SST in Summer and Its Influence Analysis

摘要: 本文利用NCEP/NCAR再分析逐月平均资料、1951~2010年的海表温度资料和我国160站夏季降水等资料，探讨研究了西太平洋暖池海温在1951~2010年夏季的年际变化及其对大气环流和我国夏季降水的影响，进而得出西太平洋暖池影响我国夏季降水的可能原因。研究结果表明，夏季西太平洋暖池海温在1951~2010年50年间发生了明显的年际变化并且具有以下特征，其与东亚地区的海平面气压场以及500 hPa的位势高度场都有着很好的正相关关系，在海温偏高年亚洲低压和东亚夏季风都有明显的减弱，而西太平洋副热带高压加强使得我国长江以南地区的夏季降水明显偏多；在海温偏低年亚洲低压和东亚夏季风会加强，西太平洋副热带高压减弱，使得我国长江以南地区的夏季降水明显偏少。

Abstract: Based on the NCEP/NCAR reanalysis monthly mean data, the SST data from 1951 to 2010 and the summer precipitation data of 160 stations in China, the interannual variation characteristics of SST during 1951 to 2010 over the Western Pacific Warm pool and its influence on summer precipitation and atmospheric circulation in China are investigated. The possible reasons for the influence of the Western Pacific Warm pool on summer precipitation in China are obtained. The results show that the Western Pacific warm pool SST of summer has obvious interannual variation characteristics from 1951 to 2010. The SST of the Warm pool is positively correlated with the sea level pressure field in East Asia and 500 hPa geopotential height field. In the year of high SST, the Asian thermal low and East Asian summer monsoon will weaken, and the subtropical high of the West Pacific will strengthen, which makes the summer precipitation in the south of the Yangtze River in China obviously more. In the lower SST years, the Asian thermal low and East Asian summer monsoon will be strengthened, and the Western Pacific subtropical high will be weakened, leading to significantly less summer precipitation in the region south of the Yangtze River in China.