东亚夏季风环流的动力统计诊断

The dynamic-statistical diagnostic for circulation of the East Asian Summer Monsoon

本文对东亚夏季风环流作了动力统计诊断,其方法是将高、低层的偏差风场看作一个整体进行复EOF分析。诊断结果表明:偏差风场的第一模态直接与东亚夏季风环流有关,可称为季风模态;第二模态则与PJ波列关系密切,可称为PJ模态;季风模态存在两个平衡态,东亚夏季风也有两个平衡态;季风模态存在强弱的年际变化,其与东亚夏季风强弱的年际变化和菲律宾附近对流的年际变化均具有很好的对应关系;东亚夏季风和季风模态还存在明显的年代际变化。

The East Asian summer monsoon circulation has been studied in this paper by dynamic-statistic diagnosis, which is analyzed by the method of CEOF regarding departure wind field in different levels as a whole. The results indicate that the first mode of departure wind field called monsoon mode relates directly with summer monsoon circulation of East Asia and it exists close relationship between PJ wave train and the second mode which can be called PJ mode. There are two equilibrium states of the monsoon mode the same as summer monsoon of East Asia. The intensity of monsoon mode have interannual variety which is prime corresponding connections with both that of summer monsoon of East Asia and the convection near Philippine. The summer monsoon of East Asia and monsoon mode also has obvious interdecadal changes.