1990—2009年中国大陆主汛期降水的变化特征及其可能原因

Analysis of Summer Precipitation Change over China for Last 20 Years and the Possible Causes

利用我国160个台站1951—2010年逐月降水观测资料,分析了我国1990—2009年夏季(6—8月)降水的变化特征,对其代表性雨型进行了分类,重点分析了1990年代和2000年代主要多雨带的变化特征。此外还分析了1990年代和2000年代的北半球500 hPa大尺度环流背景和气温及海温背景的差异,从而探讨了夏季降水年代际变化的可能原因。分析结果表明:1990年代长江流域汛期降水异常偏多,而2000年代主要多雨带北移到了淮河流域;多雨带北移的主要原因可能与2000年代全球气候异常变暖和海陆热力差异加大有关。

The variations of summer precipitation in China for the last 20 years are analyzed by using the observed data at 160 stations during 1951—2009.The characteristics of the summer rain belt in China during 1990—1999 and 2000—2009 are also analyzed.In order to explain the cause of the variability of summer rainfall,the 500 hPa geo-potential height in northern hemisphere and sea surface temperature over Pacific during 1990—1999 and 2000—2009 are analyzed.The results show that the summer precipitation in the Yangtze River basin was above normal during 1990—1999;the rain belt moved northward to the Huaihe River Basin during 2000—2009;and this moving is largely caused by the global warming in 21st century and the increased land sea thermal contrast.