两次强降水风暴双偏振参量特征分析

Analysis on characteristics of dual-polarization parameters of two heavy precipitation storms

基于济南S波段双偏振多普勒天气雷达探测数据,结合探空和地面实况资料,对2019年同一区域两次强降水风暴双偏振参量特征进行分析。结果表明:1)两次对流性强降水发生在弱垂直风切变环境下,具有较强的对流有效位能,低层湿度较大,0℃层高度较高,利于短时强降水的产生。2)两次强降水风暴都具有低质心热带降水特征,45 dBZ以上的强回波区主要位于环境0℃层高度之下。3)风暴低层强回波区都对应大的差分反射率因子ZDR和比差分相位KDP,ZDR≥0.5 dB,KDP≥0.5°·km^-1,相关系数CC≥0.95;反射率因子在50~54 dBZ之间,对应的KDP>1.0°·km^-1,CC≥0.97,ZDR适中,是两次强降水风暴导致高强度降水的主要双偏振参量特征。4)两次强降水风暴ZDR柱和KDP柱高度存在明显差异,7月27日强降水风暴前侧出现ZDR柱和KDP柱,高度接近-10℃层高度,8月10日强降水风暴ZDR柱和KDP柱略高于0℃层高度,ZDR柱高度对雷暴强度具有指示作用。

Based on the S-band dual-polarization Doppler weather radar data of Jinan,combined with sounding and surface meteorological observation data,the characteristics of dual-polarization parameters of two heavy precipitation storms that occurred in the same area in 2019 are analyzed.The results are shown below.1)The two convective precipitation processes occur in a favorable environment with weak vertical wind shear,strong convective available potential energy,high humidity in the lower layer,and high 0℃layer,which are conducive to the occurrence of short-time precipitation.2)The two heavy precipitation storms are characterized by low-centroid tropical rainfall,and the zone of high reflectivity above 45 dBZ is mainly located below the 0℃layer of the environment.3)The zone of high reflectivity in the lower layer of the storm corresponds to large ZDR and KDP values with ZDR equal to or higher than 0.5 dB,KDP equal to or higher than 0.5°·km^-1,and CC equal to or higher than 0.95.The main dual-polarization parameters of high-intensity precipitation are featured by reflectivity between 50 dBZ and 54 dBZ,KDP higher than 1.0°·km^-1,CC equal to or higher than 0.97,and moderate ZDR between 0.5 dB and 2 dB.4)There is a significant difference in the height of ZDR columns and KDP columns during the two heavy precipitation storms.The ZDR column and KDP column appear in front of the heavy precipitation storm with the height approaching the-10℃layer on 27 July,while the ZDR column and KDP column are slightly higher than the 0℃layer on 10 August.The height of ZDR column has an indicative effect on the intensity of thunderstorm.