2019年6月16日—17日沙湾强降水成因分析

The Causes of Heavy Precipitation in Shawan County Town from June 16th to 17th,2019

利用常规观测、多普勒天气雷达、FY4卫星、EC细网格及NECP/NCAR再分析等资料,分析2019年6月16日21时至17日00时沙湾县短时强降水成因,结果表明:短时强降水发生在200hPa西南气流出口区左侧,500hPa短波槽前,700hPa低空急流以及切变线前方等有利天气背景下;低层辐合、高层辐散、充足的水汽、较强CAPE和较大K指数为短时强降水提供有利环境条件;低层条件不稳定蓄积了不稳定能量,较强的水汽辐合,地面风切变触发对流是其主要原因;降水最强时段TBB降至最低,降水区位于TBB梯度最大区,中尺度对流云团及对流单体是造成短时强降水的中小尺度系统。

Based on the data of conventional observation,Doppler weather radar,FY4 satellite,EC fine grid and NECP/NCAR reanalysis,the causes of short-term heavy precipitation in Shawan county from 21:00 to 17:00 on June 16,2019 are analyzed.The results show that the short-term heavy precipitation occurs in the favorable weather background of the exit area of the southwest air flow of 200hPa,in front of the 500hPa short wave trough,the 700hPa low-level jet and the front of the shear line High level divergence,sufficient water vapor,strong cape and large K index provide favorable environmental conditions for short-term heavy rainfall;unstable low-level conditions accumulate unstable energy,strong water vapor convergence,and convection triggered by surface wind shear are the main reasons;during the strongest precipitation period,TBB decreases to the lowest,the precipitation area is located in the maximum TBB gradient area,and mesoscale convective cloud clusters and convective cells are responsible for the short-term heavy rainfall small and medium scale systems of hourly heavy rainfall.