2018-7-5梵净山东侧局地大暴雨的雷达回波特征及地形作用分析

A Sudy on The Mesoscale and The Impact of Terrain Growth on The Heavy Rainfall Event in Tongren on 5 July 2018

该文利用常规气象观测资料、区域自动站加密观测资料、NCEP逐6h的1°×1°再分析格点资料和铜仁市多普勒雷达探测资料,对2018年7月5日铜仁梵净山区域的大暴雨天气过程中尺度系统活动特征进行分析,结果表明:高空槽、低层切变线,叠加高低空不稳定的高湿区是此次大暴雨形成的大尺度环境背景。且强降水对流回波沿着地面辐合线形成发展,地面辐合线为强降水对流系统的重要触发机制。梵净山地形的抬升作用,对江口北部及松桃北部地区雨强有增强作用,从而导致大暴雨的发生。当梵净山东侧为东南风时,地形辐合抬升作用,利于江口北部降雨增强;当梵净山东北侧为东北偏北风时,利于松桃境内降雨增大。

Based on conventional meteorological observation data,regional automatic station observation data,NCEP reanalysis grid data of 1°×1°every 6 hours and Tongren Doppler radar detection data,the activity characteristics of the mesoscale system during the heavy rain weather process in Fanjing Mountain area of Tongren on July 5,2018 were analyzed.The results show that the large scale environmental background of the heavy rain is the upper trough,the lower level shear line and the high humidity area with unstable upper and lower level.In addition,the convective echoes of heavy precipitation are formed and developed along the surface convergence line,which is an important triggering mechanism of the heavy precipitation convective system.The uplift of Fanjing Mountain enhanced the rain intensity in the northern part of Jiangkou and Songtao,leading to the occurrence of heavy rain.When the southeast wind is on the east side of Fanjing Mountain,the terrain converging and lifting effect is beneficial to the rainfall enhancement in the north of Jiangkou.When the northeast side of Fanjing Mountain is northeasterly wind,the rainfall increases in Songtao.