强热带风暴碧利斯特大暴雨山洪成因分析

利用常规观测资料及候平均要素等资料,从前期天气背景、大气环流演变及产生强降水的动力、热力、水汽和不稳定条件,分析了0604号强热带风暴碧利斯登陆后在湘东南产生的特大暴雨过程。结果发现地面中尺度辐合线产生的上升运动与地形的动力抬升结合,加强了特大暴雨产生的动力作用,高温高湿有利于扰动形成和对流不稳定能量产生,为湘东南特大暴雨产生提供了极好的热力条件,南海季风爆发及西南季风槽的形成为湘东南暴雨上空提供了源源不断的水汽,大陆高压与副高对峙导致了"碧利斯"在西移过程中减缓。造成湘东南特大暴雨山洪除了气象成因外,薄弱的地质环境条件是"碧利斯"得以诱发地质灾害的内因。

Causality Analysis of Super Rainstorm and Mountain Torrents by Strong Tropical Storm "BILIS"

Based on the weather background,atmospheric circulation evolution and the meteorological conditions,including dynamic,thermodynamic,water vapor and the instability condition,the torrential rain in the southeast of Hunan Province caused by "BILIS"(the No.4 strong tropical storm in 2006)is examined by using the conventional observations and pentad-averaged meteorological elements.Results show that the ascending motion generated by the surface meso-scale convergence line and the dynamic lifting of topography strengthened the dynamic force of torrential rain.In addition,the high temperature and high humidity provided extremely good thermal energy,which is propitious to the development and the generation of convective instability energy.The eruption of the South China Sea monsoon and the formation of monsoon trough in the southwest offered water vapor continuously.Moreover,the continental high and subtropical high confronted each other and slow down the westward drift of "BILIS".Besides the meteorological factors,the frangible geology environmental condition is the internal cause of the geological disaster induced by "BILIS".