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利用热带测雨卫星的测雨雷达 (TRMMPR)的探测结果 ,对 1 997 1 998年ElNin～o后期热带太平洋的降水结构进行了研究 ,并对比了非ElNin～o的 1 999年和 2 0 0 0年的同期降水情况 ,取得如下结果 :( 1 ) 1 997 1 998ElNin～o后期与非ElNin～o期间相比 ,1 997 1 998ElNin～o后期 ,热带东、中太平洋层云降水和对流云降水的比例明显增大、平均降水率也增大 ,并且层云强降水的比例增多 ,而层云弱降水比例减少。 ( 2 )在非ElNin～o期间 ,热带东、中太平洋对流云降水系统较为浅薄 ,冻结层高度比西太平洋低约 0 5km ;而在 1 997 1 998ElNin～o后期 ,这种差异明显减小 ,热带东、中太平洋对流云降水和层云降水都变得深厚 ;对流云降水和层云降水的降水率随高度的变化也发生了变化。 ( 3)对大气环流的分析表明 ,对应于降水结构的变化 ,热带太平洋地区的高空辐合辐散分布也发生了改变 ,导致Walker环流在 1 997 1 998ElNin～o后期减弱。
Based on the results of TRMMPR measurements, the precipitation structure of the tropical El Pacific Ocean in the late El Niño period of 1 991-1998 was studied and compared with that of non-Elinan waves in 1999 and 2000 (1) The period of 1 997 1998ElNin ~ o late and non-El Nin ~ o period, 1 997 1998ElNin ~ o Late, the tropical eastern and central Pacific stratospheric and convective cloud precipitation , The average precipitation rate also increased, and the proportion of stratospheric heavy precipitation increased while the proportion of stratospheric cloud weak precipitation decreased. (2) During the non-El Nino period, the convective cloud precipitation in the tropical and central Pacific was shallow and the height of the frozen layer was about 0 5 km lower than that in the western Pacific. However, in the late period of 997 1998ElNin-o, Convective cloud precipitation and stratospheric precipitation in tropical eastern and central Pacific Ocean have become deep; precipitation precipitation and stratospheric precipitation precipitation changes with height also changed. (3) The analysis of the general circulation shows that the distribution of divergence and divergence at high altitude in the tropical Pacific has also changed corresponding to the change of precipitation structure, resulting in the Walker circulation weakened in the late period of 1 997-1998ElNin-o.