Some Features of Walker and Hadley Circulations During the Period of Torrential Rain in 1991

In this paper, a study on Walker and Hadley circulations over the Yangtze and Huaihe River Valleys in 1991 has been made. The areas for Walker and Hadley circulation analyses are in the Equatorial Pacific and along 115°E, respectively. It is found that the torrential rain and flood in 1991 correspondings to the situations of the weakening easterlies and the strengthening westerlies. An anti-Hadley circulation (i. e. the eastern-Asia monsoon circulation) can also be seen and strengthened over the eastern China. Analyses of divergence wind field indicate that a cross-equatorial current of divergence wind is found in the lower troposphere and out-flow current in the upper troposphere during the torrential rain period