3个深入内陆热带气旋产生大暴雨的成因——对比分析

利用常规气象观测资料、NCEP等资料,对2006年3个深入内陆的热带气旋产生大暴雨的水汽、动力和热力条件进行了对比分析。结果表明:(1)碧利斯虽强度属3个热带气旋中最弱的一个(只达强热带风暴等级),但由于它与南侧强西南季风结合,使其产生暴雨的水汽、动力和热力条件异常强盛,因而导致其暴雨强度最强、范围最大、灾害最严重;(2)螺旋度垂直分量20×10-7hPa.s-2等值线包围区的水平范围和螺旋度正值区垂直伸展高度及各层中心值强度与暴雨强弱有较好的关系,且暴雨区主要落在700 hPa 20×10-7hPa.s-2等值线包围区内;(3)暴雨发生时,3个热带气旋的湿位涡MPV1场均呈现下负上正分布,说明低层为不稳定层,同时均出现高层MPV1正值区向低层下伸的现象,反映不稳定能量开始释放;(4)由于3个热带气旋均未与冷空气结合,故MPV2值均较小,因此湿位涡的湿正压项(MPV1)对产生暴雨的作用大于湿斜压项(MPV2)。

Formation cause of three heavy rainstorms induced by tropical cyclones invading interior territory:comparative analysis

For three tropical cyclones(Bilis,Saomai and kaemi) happened in 2006 that invaded into the interior territory and resulted in the relative strong rainstorm,we comparatively analyzed the vapor and dynamical condition,the unstable energy and the moist potential vorticity.The results show that although Bilis just reaches the degree of the strong tropical storm,it induces extremely strong vapor,dynamical,and thermal conditions much stronger than Saomai and Kaemi,after Bilis landes the territory and combined wit...