一次台风低压倒槽和切变线接连影响的暴雨过程分析

A Torrential Rain Process Analysis Influenced by Typhoon Low Down Trough and Shear Line

2013年8月22日凌晨2时40分,第12号台风"潭美"在福建省福清市沿海登陆.登陆后,"潭美"向西偏北方向移动,移至江西与湖南交界处附近转向西偏南方向移动,不仅给沿途带来强风暴雨,其外围倒槽影响我国黄淮、江南、西南大片区域,造成不同程度的强降水.这次区域暴雨过程分为两部分,前一部分为"潭美"外围倒槽云系造成,后一部分转为低槽切变线影响,转折在24日早晨,倒槽的尾部与南压的切变线西段有一个叠加结合,切变线北侧配合干冷空气切入,垂直切变增大,这个时段降水强度加大.湿层深厚并且水汽输送源源不断,为这次暴雨过程提供了充足的水汽条件.后期转为低槽切变线影响,冷空气配合,上升运动明显增加,为降水强度增大提供了有利动力和不稳定条件.对这次暴雨过程的分析,提示在考虑登陆台风倒槽影响所产生降水时,特别要注意北方是否有低槽冷空气配合,如果有,则极易产生强降水.

No. twelfth typhoon ＂Trami＂ landed in Fuqing city the morning. After landing, ＂Trami＂ moved in the direction of of Fujian Province on August 22, 2013 at two forty in North West, then turned to west south direction near the junction of Jiangxi and Hunan. It bring strong winds and rain along the way. The periphery trough influences China＇ s Huang Huai, south of the Yangtze River and southwest of large areas, causing strong precipitation in different degree. The regional rainstorm process is divided into two parts. The front part is caused by peripheral trough cloud of ＂Trami＂. The other part is influenced by the low trough and the shear line. It turned a superposition combination between the trough tail and a south pressure by the west of the shear line on the morning of August 24. Then with dry cold cuts in the north of shear line, the vertical shear increases, precipitation intensity of this period of time. Wet layer and deep water vapor transport stream provides ample moisture conditions for the heavy rain. Later the low trough impacts with the cold air, which increase the upward movement, providing favorable dynamic and unstable conditions for the increasing of the precipitation intensity.