1991年夏暴雨期间Walker环流和Hadley环流的特征

SOME FEATURES OF WALKER AND HADLEY CIRCULATIONS DURING THE PERIOD OF TORRENTIAL RAIN IN 1991

该文分析了1991年7月中国江淮暴雨洪水期间赤道太平洋沃克环流及沿115°E 哈得莱环流的逐日演变特征。结果发现在暴雨时期赤道东风减弱,西风加强,反哈得莱环流(即季风环流)在中国东部上空加强。在暴雨期间,高低空散度风场的分析指出,在低空出现明显的散度风越赤道气流,而在对流层上部出现散度风的流出。

In this paper,a study on Walker and Hadley Circulations over the Yangtze andHuaihe River Valleys in 1991 has been made.The areas for Walker and Hadley circula-tion analyses are in the Equatorial Pacific and along 115°E,respectively.It is found thatthe torrential rain and flood in 1991 correspondings to the situation of the weakeningeasterlies and the strenthening westerlies.An anti-Hadley circulation (i.e.the eastern-Asia monsoon circulation) can also be seen and strenthened over the eastern China.Analyses of divergence wind field indicate that a cross-equatorial current of divergencewind is found in the lower troposphere and out-flow current in the upper troposphereduring the torrential rain period.