2014年5月31日华东地区一次暖区飑线过程的多普勒天气雷达分析

Analysis on a squall line process in warm region of eastern China on May 31 2014 by Doppler radar

本研究利用美国国家海洋和大气管理局(NOAA)的Global Forecasting System(GFS)再分析资料、气象信息综合分析处理系统(MICAPS)观测资料、自动站与逐小时融合降水资料和中国新一代多普勒天气雷达网的基数据(Level-Ⅱ),对2014年5月31日一次发生在合肥附近的暖区飑线过程进行了分析。天气分析显示,飑线发生在暖区,整个中高层以下呈现高湿状态,以及较弱的对流不稳定和弱风切变(0～3 km风切小于10 m·s^(-1))环境。雷达分析揭示,飑线呈弓状,具有明显的对流区、层云区和过渡带,线尾涡旋位于弓形回波北端。从后往前的气流自层云区后侧6 km以下进入系统,最大风速区在z=4 km处,强风速中心并未及地造成地面风灾。由于本次个案在暖区高湿环境下形成,地面冷池较弱,维持时间短;短时降水较强,最强超过40 mm·h^(-1)。

A case of squall line occurred in Anhui province on 31 May 2014 was analyzed by using the National Oceanic and Atmospheric Administration＇s Global Forecasting System reanalysis data,MICAPS observation data,the Chinese CMORPH precipitation analysis data,and the network of Chinese next-generation weather radar data from China Meteorological Administration. The squall line occurred under warm and moist condition with slight instability and weak wind shear（ less than 10 m · s^-1 over 0—3 km） at low-levels. The radar echo displayed ＂bow＂shape with convective,stratiform region and a transition zone. A bookend vortex was at north of the ＂bow＂. The rear-to-front inflow entered the system from the rear of the trailing stratiform zone below 6 km,and the maximum wind speed region located at 4 km. The strong wind center of the rear-to-front flow was not reached the surface,in the results of no sur-face damages. Because of the warm and moist condition below the middle level,the cold pool was weak,and led to short-lived squall line,but the squall line produced heavy rain greater than 40 mm h^-1.