孟加拉湾低压与昆明准静止锋影响下云南极端暴雨过程分析

The Analysis of Extreme Rainstorm Process as Influenced by the Bay of Bengal low and Kunming Quasi-stationary Front in Yunnan

利用水平分辨率为1°×1°逐6小时FNL再分析资料、常规观测资料和FY-2E观测资料,诊断分析了2015年10月9日云南极端暴雨过程。结果表明:此次云南极端暴雨是由孟加拉湾低压和昆明准静止锋共同作用造成;孟加拉湾低压登陆后长时间维持提供了源源不断的水汽供应,700 hPa切变线和昆明准静止锋使水汽辐合明显增强;在高低空急流和锋面抬升作用下上升运动得到强烈发展;受地形和锋面抬升,在潮湿大气中存在倾斜上升运动有利于条件性对称不稳定能量的释放。

The formation mechanism of an extreme rainstorm process in Yunnan on October 9th,2015 was analyzed using FNL reanalysis data,conventional observation,and FY-2E satellite observatory data.Results showed that this extreme rainstorm in Yunnan was caused by the Bay of Bengal low combined with Kunming quasi-stationary front.The Bay of Bengal low maintained for a long time after landing,which provided long-lasting and abundant supply of water vapor.The shear line at 700 hPa and Kunming quasi-stationary front greatly enhanced the water vapor convergence.Rising movement was strongly developed because of high-level and low-level jet streams and frontal lifting.The slantwise updraft by the orographic uplift and frontal lift was favorable to the release of conditional symmetric unstable energy in moisture air.