湘东北一次降雹超级单体过程的双偏振雷达回波特征  

Dual-polarization radar echo characteristics of a hail supercell event in northeastern Hunan

作　　者：陈龙 唐明晖 唐佳 胡媚 王青霞 CHEN Long;TANG Minghui;TANG Jia;HU Mei;WANG Qingxia(Hunan Meteorological Observatory,Changsha 410118;Meteorological Disaster Prevention and Reduction Key Laboratory of Hunan Province,Changsha 410118)

机构地区：[1]湖南省气象台,长沙410118 [2]气象防灾减灾湖南省重点实验室,长沙410118

出　　处：《暴雨灾害》2023年第2期211-222,共12页Torrential Rain and Disasters

基　　金：湖南省重点领域研发计划项目(2019SK2161);湖南省气象局重点项目(XQKJ17A002);中国气象局创新发展专项(CXFZ2021Z033)。

摘　　要：利用S波段双偏振雷达资料和多种观测资料,对2021年5月10日湖南长沙的大冰雹超级单体风暴过程进行分析,结果表明:(1)此次过程发生在低层暖平流主导下,高能量、有利的对流不稳定条件以及湿球0℃(WBZ)高度明显低于0℃层高度为大冰雹超级单体风暴的形成和维持提供了有利条件。(2)强中心(水平反射率因子Zh≥60 dBz)面积和最大水平反射率因子明显增大、垂直累积液态水含量跃增和质心高度发展到冰雹有效增长层,可作为大冰雹形成发展的依据。(3)差分反射率因子(Z_(dr))柱、相关系数(CC)、差分相移率(K_(dp))演变可为冰雹的云物理特征变化提供重要参考。Z_(dr)柱(≥1 dB)的出现对应上升气流区,扩展至WBZ以上,Z_(dr)柱的发展和维持表明其携带的过冷雨滴为冰雹发展和维持提供了雹胚;Z_(dr)洞(<0 dB)对应下沉气流区扩展至近地面,结合小CC和K_(dp)“空洞”对应干的大冰雹。(4)构建的超级单体风暴降雹阶段不同仰角的双偏振监测识别模型显示,强雹暴回波离开雷达一侧存在降水回波,导致Zh的三体散射特征不明显,Z_(dr)和CC表现的偏振三体散射特征和非均匀波束充塞延伸距离可作为识别冰雹及其尺度的重要判据。Using S-band dual-polarization radar data and other observation data,a supercell storm that caused a large hail in Changsha,Hunan Province on 10 May,2021 was analyzed.The results show as below.(1)This process takes place under the synoptic condition of low-level warm advection,high energy,and convective instability.Besides,wet bulb 0℃(WBZ)is obviously lower than the height of 0℃,which provided favorable conditions for the formation and maintenance of large hail supercell storms.(2)The area of strong center(horizontal reflectivity(Zh)≥60 dBz)and the maximum horizontal reflectivity increase significantly.The vertical integrated liquid water content increases significantly,and the height of mass center develops to reach the effective growth layer of hail,which can be used as a criterion of major hail formation and development.(3)The evolution of differential reflectivity(Z_(dr))column,correlation coefficient(CC),and specific differential phase(K_(dp))provides the important basis for distinguishing the changes in the cloud physical process of hail.In the early stage of storm development,the appearance of Z_(dr) column corresponds to the updraft zone,which extends above WBZ.The supercooled raindrops in the Zdr column provide hail embryos for the development of hail.The Z_(dr)-hole(<0 dB)corresponds to the downdraft area and expands to near the ground.Small CC and K_(dp)-hole indicate the appearance of dry large hail.(4)The dual-polarization monitoring and identification model of hail supercell is constructed and which shows that due to the occlusion of precipitation echo,Zh does not show the characteristics of three body scatter spike(TBSS).The polarization TBSS characteristics of significantly negative Zdr and small CC and non-uniform beam filling can be used as an important criteria for identifying hail and hail scales.

关 键 词：大冰雹 超级单体风暴 双偏振雷达 偏振参数 

分 类 号：P412.25[天文地球—大气科学及气象学]