登陆热带气旋引发的龙卷过程之个例分析

将卫星云图与物理量场相结合，对9909号热带风暴（WENDY）登陆北上并与西风带系统相互作用，引发上海东南部地区龙卷天气的过程进行分析研究，发现中低纬度系统的相互作用使WENDY倒槽得以维持和发展，并对WENDY残存低压长时间存在并北上起重要作用，当WENDY低压北上与西风带系统相接、叠加时，高层辐散、低层辐合的良好环境使WENDY环流内的对流云团进一步加强发展，中尺度干涌的涌入促使强对流云团群合并发展，并加剧对流辐合体内水平风切变，最终导致龙卷产生。

A Case Analysis of Tornado Triggered by Landing Tropical Cyclone

In early September 1999,a tropical storm(WENDY)landed,moved northeast,then interacted with the trough in mid latitudes and finally, produced tornado in the southeastern Shanghai. Combined satellite cloud pictures with physical quantities, it is found that interaction of systems between middle and low latitude made WENDY inverted trough maintenance and development, also play an important role for WENDY moving to north. When WENDY connected with westerly system , good environment of higher level divergence and lower level convergence strengthened the development of convective cloud. East moving of the mesoscale dry surge intensified the horizontal wind shear, at last caused the tornado.