北太平洋次表层海温异常对中国夏季降水影响的可能途径

The Possible Influence Channel of Sub-surface Sea Temperature Anomaly in the North Pacific on China Summer Rainfall

利用Godas月平均次表层海温资料,分析了冬、春季和夏季北太平洋次表层海温层际相似性特征,据此对次表层海温进行分层。在此基础上研究了500hPa位势高度场、北太平洋次表层海温、中国夏季降水三者之间的时滞相关关系,发现春季北太平洋次表层海温场是联系前、后期大气环流的关键因素。前期冬季大气环流对春季北太平洋次表层海温场影响最显著,春季北太平洋次表层海温场又持续影响同期及后期夏季大气环流异常。异常的夏季大气环流与同期表层、次表层海温相互作用,共同造成夏季长江流域与华北、华南降水出现相反异常的分布型式。

By use of Godas monthly sub-surface sea temperature （ST）,the similarity of ST among different layers is analyzed,and ST is layered in the North Pacific region for winter,spring,and summer.The time-lag correlations among the 500-hPa geopotential height field,sub-surface sea temperature field in the North Pacific,and the summer rainfall in China are further studied.Results show that the sub-surface ST in spring is an important factor linking the anterior and posterior atmospheric circulation.Atmospheric circulation in winter has a most remarkable influence on the ST in the North Pacific in spring,and the ST in spring also has persistent effects on atmospheric circulation for the corresponding period and the later summer.The interactions between atmospheric circulation and the sea surface,sub-surface temperature anomalies respectively lead to the opposite anomalous pattern of precipitation for the Yangtze River basin with North China and South China in summer.