旱、涝年与海气相互作用

AIR SEA INTERACTION IN DRY AND WET YEARS

利用１９５１～１９９１年５００ｈＰａ高度场和海温场以及１９８０～１９９１年ＴＢＢ资料，采用合成分析方法研究了东亚季风区季节转换在旱、涝年的不同特征。发现旱、涝年海温场分布型的不同及其形成的海气相互作用的差异使得西太平洋副热带高压在涝年季节北进较平缓，其脊线位置稳定在２５°Ｎ左右，强度较强，从而导致夏季风雨带在江淮流域停滞，形成江淮洪涝。文中还讨论了中南半岛对流和赤道干旱带的变化对江淮流域旱、涝的先兆作用。

Using 1951～1991 500 hPa height and SST, and 1980～1991 T BB data, study is undertaken of the features of east Asian monsoon seasonal transition in dry and wet years by means of composite analysis, indicating that different SST patterns and difference in the related air sea interaction are responsible for slow northerly march of western Pacific subtropical highs on a seasonal basis, with the stronger ridge steadily located around 25°N, causing the summer monsoon rainband persisting in the Jiang Huai drainages for flood. Further, addressed are the effects of the Indo China convection and the change in a equatorial high pressure band as forerunners upon the Jiang Huai flood/drought.