冬季流入南印度洋的低空越赤道气流分析

A STUDY OF CROSS-EQUATORIAL FLOW INTO THE SOUTH INDIAN OCEAN IN THE LOWER TROPOSPHERE DURING THE WINTER

本文利用1980—1987年850hPa 格点风资料和500hPa 高度场资料,分析了冬季自北半球流入南印度洋的越赤道气流的特征,指出在35°—135°E 的近赤道地区冬季低空有四支源自北半球的越赤道气流,它们具有明显的年变化和年际变化;它们主要来自阿拉伯半岛—东亚地区大陆冷高压的东北季风,其强弱变化取决于东北季风的活动。

The cross-equatorial flow that comes from the Northern Hemisphere into the South IndianOcean in the lower troposphere during the winter has been investigated using grid point wind dataat 850hPa and the data of geopotential height field at 500hPa during 1980-1987.It points outthat there are four channels of cross-equatorial flow coming from the Northern Hemisphere nearthe equatorial area from 35°E to 135°E and they are characterized by considerable annual and in-terannual variations.The four channels of cross-equatorial flow mainly come from the northeastmonsoon of continental cold highs ranging from Arabian peninsula through East Asia,the intensi-ty of flow depends on the northeast monsoon activities.