东半球跨赤道气流季节变化的研究

SEASONAL VARIATION OF CROSS EQUATORIAL FLOW OVER THE EAST HEMISPHERE

跨赤道气流作为季风环流系统的组成部分,一直被气象工作者所重视。Findlater(1969)第一次证实了夏半年索马里急流的存在,陈于湘得出夏季季风区有105°E和150°E两支跨赤道气流,冯颖竹等人确定出索马里急流、印度尼西亚气流、青藏高原所在经度上的中低空向南气流以及印度尼西亚高空向南气流的存在,李曾中也得到了类似的结果。由以上研究可以看出,他们的许多结论是一致的,但是,这些研究大多数是局限于夏半年以及某些层次上。

In this paper, the seasonal variation of cross equatorial flow over the east hemisphere is analyzed by using six level monthly mean wind data from Jaunary 1979 to December 1987. The results are as follows: the maximum of the absolute magnitude of the cross equatorial flow does exist at lower level of troposphere in winter and summer but at higher level of troposphere in spring and fall. The cross equatorial flow propagates southward in winter and fall but northward in summer and spring. The time when the propagating direction of the meridional wind component at equator changes is March and November at lower level but June and January at higher level.