2020年5月22日广州强降水超级单体的S波段双偏振雷达回波分析

Analysis of S-band Dual-polarization radar echo of heavy precipitation supercell in Guangzhou on May 22,2020

为研究S波段双偏振雷达探测强降水超级单体的回波特征,本文利用广州S波段双偏振雷达、风廓线雷达、气象信息综合处理系统(Meteorology Information Comprehensive Analysis Process System,MICAPS)、地面观测站等资料,分析了2020年5月22日广州一次局地特大暴雨过程的发生发展及雷达回波特征。结果表明:列车效应和后向传播影响共同造成了广州此次局地强降水过程;强降水超级单体成熟阶段,雷达回波低层仰角会出现K_(DP)印,ρHV图上有非均匀波束填充(Non-Uniform Beam Filling,NUBF)特征,高层仰角会出现Z_(DR)环(高值区)、ρHV环(低值区)等特征,垂直方向上表现为形态相似、空间分布分离的Z_(DR)柱和K_(DP)柱;Z_(DR)最大值略早于Z_(H)最大值,一般出现在Z_(H)骤增时段,雨强开始增大或最大雨强之前,对强降水的发展有指示意义,K_(DP)最大值一般出现在Z_(H)大值时段,并与最强降水时段对应,结合Z_(DR)和K_(DP)可以更好地判断降雨强度的变化。

In order to study the echo characteristics of heavy precipitation supercells detected by S-band Dual-polarization radar,this paper presents a detailed analysis of the occurrence and development of a local super heavy rainfall process and its radar characteristics in Guangzhou on 22 May 2020 by using data from S-band Dual-polarization radar,wind profile radar,MICAPS and ground observation stations in Guangzhou.The results show that the train effect mechanism and the back-propagation effect jointly caused the local torrential rain event in Guangzhou.During the mature stage of a heavy precipitation supercell,K_(DP) prints appear in the lower elevation angles of the radar map,the Non-Uniform Beam Filling(NUBF)characteristics appear on theρHV maps,and Z_(DR) rings(high value areas)andρHV rings(low value areas)appear at high elevation angles.In the vertical direction,the Z_(DR) column and K_(DP) column are similar in shape and separated in spatial distribution.The occurrence of maximum value of Z_(DR),which is indicative of the development of heavy rainfall,is slightly earlier than the maximum value of Z_(H),and it normally occurs during the period of sudden increase of Z_(H) and the timing of rain intensity starts to increase or before the maximum rain intensity.The maximum value of K_(DP) normally occurs during the period of maximum Z_(H).Corresponding to the period of the strongest precipitation,the rainfall intensity can be identified by combining with Z_(DR) and K_(DP) value.