2017年7月初柳州特大暴雨成因分析

Cause Analysis of Extreme Heavy Rain in Liuzhou in Early July 2017

利用常规气象观测资料和柳州多普勒雷达观测资料,采用天气学诊断分析方法,对2017年7月1-2日发生在柳州市的一次特强降水过程进行了分析。结果表明:高原槽、低涡切变以及地面辐合线是此次过程的主要影响系统;副热带高压的稳定维持,使高原槽长时间停滞在黔桂交界一带;地面中尺度辐合线的长久维持为强降水提供了动力抬升的条件,辐合上升运动增强激发出大量的中尺度对流云团,强回波形成列车效应,从而产生大暴雨。

Using the conventional meteorological observation data and the Doppler radar observation data,a heavy precipitation process in Liuzhou from July 1 to 2,2017 was analyzed by the method of synoptic diagnostic analysis. The results showed that the plateau trough,low eddy shear and surface convergence line are the main influence systems of this process. The stability of subtropical high makes the plateau trough stagnate at the junction of Guizhou and Guangxi for a long time;The long-term maintenance of surface mesoscale convergence line provided the dynamic uplift;the enhanced convergence which stimulates a large number of convective clouds,resulting the heavy rain.