全球越赤道气流基本特征

The Major Characteristics of Global Air Current Across the Equator

本文主要利用1973～1989年逐月全球热带200hPa及850hPa层经、纬向格点风及1980年以来1000,850,700,500,200,100,50hPa各层经纬向格点风,确定了热带对流层高、低(200,850hPa)层具有气候意义的越赤道气流通道,并分析了各越赤道气流通道强度的时、空变化特征。指出东半球比西半球越赤道气流强且稳定,季节变化也较明显。文章还指出,低层东半球向夏半球输送,高层夏半球向冬半球输送,且高、低层各相应通道强度变化趋势基本一致。高层与低层相比较,低层通道强且稳定,季节变化规律也较明显。文章还讨论了越赤道气流与大气环流系统的密切关系,指出各通道强度的年际变化是南、北两半球大尺度海-气相互作用的重要组成部分,是全球大气环流异常变化的重要信息。

By using monthly meridional and zonal wind at grid point of 200hpa and 850hPa level in the global tropical ocean from 1973 to 1989, and at grid point of 10013, 850, 700, 500, 200, 100, 50hPa level from 1980 to 1989, in this paper, the higher and lower layer of troposphere (200, 850hPa) are considered climatically as air current passage across the equator, and the temporal and spatial variation characteristics of the strength for various air current passages across the equator are analyzed. The resultsshow that the air current across the equator in the Eastern Hemisphere is stronger and more stable than that in the Western Hemisphere, and also has obvious seasonal variation. It is further pointed out that air current is transported from the winter hemisphere to the summer hemisphere in the lower layer, conversely from the summer hemisphere to the winter hemisphere in the higher layer, and also indicated the trends of passage intensity variations in the higher layer and lower layer are basically the same. Compared with the higher layer, the passage intensity in the lower layer is more stable and has more evident seasonal variation. The close relationship between air current across the equator and air circulation system are discussed, the results indicate that the annual variations of the various passage intensities reflect the variations of large scale air-sea interactions in the Northern and Southern Hemisphere and is an important information about the global air circulation variability.