台风"麦莎"(0509)登陆北上变性加强过程的诊断分析

以一个在陆上长久维持并最终演变成温带气旋的登陆台风“麦莎”为研究对象,通过对其北上变性过程的分析发现,台风与中高纬西风槽的相互作用使得冷空气侵入是其变性加强的原因。高层位涡的变化可清楚揭示台风变性加强的物理过程,分析表明,“麦莎”变性过程中有高层正位涡下传的现象。在台风结构上,从变性前的垂直对称分布演变为倾斜的非对称分布。

Diagnostic Analysis of the Extratropical Transition Process of the Landfall Typhoon Matsa (0509)

A study was carried out on the landfall typhoon 0509 Matsa,which sustained over land for a long period and was transformed into an extratropical cyclone in the end. Through the analysis, it is shown that the Matsa's extratropical transition and the re-intensification are due to the intrusion of cold air from the upper-level trough into the typhoon's circulation. From the variation of potential vortices at the upper-level, one can clearly see the mechanism that its anomaly is downward transported from the upper troposphere during the typhoon's transformation. The main course is the transformation of a symmetric perpendicular cyclone to a baroclinic asymmetric cyclone.