2021年5月武汉两次对流性大风天气的多普勒雷达观测分析  

Doppler radar observation and analysis of two convective gale weather events in Wuhan in May 2021

作　　者：王珏[1] 肖艳姣[1] 冷亮[1] 付志康[1] 管振宇 WANG Jue;XIAO Yanjiao;LENG Liang;FU Zhikang;GUAN Zhenyu(Hubei key laboratory for Heavy Rain Monitoring and Warning Research,Institute of Heavy Rain,China Meteorological Administration,Wuhan 430205;Wuhan Central Meteorological Observatory,Wuhan 430074)

机构地区：[1]中国气象局武汉暴雨研究所暴雨监测预警湖北省重点实验室,武汉430205 [2]武汉中心气象台,武汉430074

出　　处：《暴雨灾害》2022年第2期119-129,共11页Torrential Rain and Disasters

基　　金：国家自然科学基金项目(U2142202);国家重点研发计划(2018YFC1507503);湖北省气象局科技发展基金项目(2022Y04)。

摘　　要：对流性大风是强风暴最常产生的天气现象,致灾严重,预报难度大。2021年5月10日和14日,湖北武汉先后发生了雷暴大风和龙卷天气过程(以下简称“5.10”大风和“5.14”龙卷)。本文利用常规探空和武汉多普勒天气雷达资料,对这2次过程的环境条件、多普勒雷达回波特征和雷达衍生参量进行了对比分析,结果表明:(1)两次过程都发生在具有高不稳定能量、强垂直风切变和低抬升凝结高度的环境中,地面都有多支气流形成的辐合区,但下沉对流有效位能、能量螺旋度、强天气指数等强对流物理参量值有显著差异;(2)两次对流性大风的产生机制和雷达回波特征不同,“5.10”大风主要由中层干冷空气和降水粒子相变发动强下沉气流产生雷暴大风,并在地面形成冷性雷暴高压。由多个对流单体合并的对流带产生的强下沉气流在径向速度场上表现为低层大风核,而对流带前侧相对孤立的单体产生的强下沉气流表现为低层径向辐散特征;“5.14”龙卷由超级单体产生,具有钩状回波、强中气旋和龙卷涡旋特征等特征;(3)两次过程发生前垂直风速差和风暴相对螺旋度的变化差异显著,表明了两次过程环境气流的变化不同,这样的变化是否适用两种天气的识别还需要对大量个例进行统计分析。Convective gale is the most common weather phenomenon of severe storms,which causes serious disasters and is difficult to pre⁃dict.Thunderstorm gales and tornado occurred successively in Wuhan on May 10 and 14,2021.In this paper,the environmental conditions,Doppler radar echo characteristics and radar derived parameters of the two events are compared and analyzed by using conventional radio⁃sonde and Wuhan Doppler weather radar data.The results show that:(1)Both events occur in the similar environment with high unstable en⁃ergy,strong vertical wind shear and low uplift condensation height.There are convergence areas formed by multiple air streams on the ground,but the physical parameters of strong convection,energy helicity and strong weather index are significantly different between the two events.(2)The generation mechanism and radar echo characteristics of the two convective gales are different.The thunderstorm gale of"5.10"was mainly caused by the strong downdraft caused by dry and cold air in the middle layer and the phase change of precipitation parti⁃cles,and by the fact that a cold thunderstorm high pressure was formed on the ground.The strong downdraft generated by the convective zone combined by multiple convective cells appears as a low-level gale core in the radial velocity field.The strong downdraft generated by the rel⁃atively isolated cell in front of the convection zone is characterized by low-level radial divergence.The"5.14"tornado is generated by super⁃cell with hook echo,strong mesocyclone and TVS.(3)There are significant differences in the changes of vertical wind shear and SRH before the two events,indicating that the changes of ambient air flow in the two events are different.Whether such changes are applicable to the identification of the two weather conditions still needs to be studied by making statistical analysis on a large number of individual cases.

关 键 词：对流性大风 环境参量 雷达观测特征 

分 类 号：P458.2[天文地球—大气科学及气象学]