东亚夏季风与中国夏季降水年际异常的分型研究

THE INTERANNUAL VARIATION OF THE EAST ASIAN MONSOON AND ITS RELATION TO SUMMER PRECIPITATION IN CHINA

以海陆气压差定义的夏季风强度指数为依据，讨论了东亚夏季风年际异常与中国夏季降水的关系。发现东亚夏季风强时，中国夏季降水可能多也可能少，但以少雨为主；季风弱时，中国降水也是或多或少，但以多雨为主。依此可以将季风与降水的异常关系分成强季风强降水（Ａ）、强季风弱降水（Ｂ）、弱季风强降水（Ｃ）、弱季风弱降水（Ｄ）四种关系型。其中（Ａ）型和（Ｄ）型、（Ｂ）型和（Ｃ）型的降水呈反相似性分布，主要特殊性反映在东北、华北以及东南等部分沿海小范围区域。夏季风环流强弱仅为中国降水异常提供背景，降水的多少及区域性差别与当时局地的天气系统有关。

The relation between the interannual variation of the east Asian summer monsoon (EASM) and the summer precipitation in China is investigated in terms of the east Asian summer monsoon intensity index. The results suggests that the summer precipitation of China is indigent in the year of stronger EASM, and abundant in the weak year. The relation shows four patterns including strong monsoon with abundant precipitation, weak monsoon with abundant precipitation, strong monsoon with indigent precipitation, weak monsoon with indigent precipitation. The summer monsoon circulation supported only the background for China's rainfall variation, and rainfall and its regional differences are related to the local weather systems at that time.