广州“5·22”致灾特大暴雨的多源资料分析——从天气尺度背景到γ-中尺度涡旋  

Analysis of the Disaster-causing Guangzhou"May 22"Extreme Rainfall Event Using Multisource Data:from Synoptic Background to Meso-γ-scale Vortices

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作  者:张佳华 罗亚丽 高艳宇[3] 肖天贵 张宇[1] 陈杨瑞雪 ZHANG Jiahua;LUO Yali;GAO Yanyu;XIAO Tiangui;ZHANG Yu;CHEN Yangruixue(College of Atmospheric Sciences,CUIT,Chengdu 610225,China;Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD),NUIST,Nanjing 210044,China;State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China)

机构地区:[1]成都信息工程大学大气科学学院,四川成都610225 [2]南京信息工程大学气象灾害预报预警与评估协同创新中心,江苏南京210044 [3]中国气象科学研究院灾害天气国家重点实验室,北京100081

出  处:《成都信息工程大学学报》2023年第3期330-339,共10页Journal of Chengdu University of Information Technology

基  金:国家自然科学基金资助项目(42030610)。

摘  要:为提高对季风海岸极端降水成因机制的认识,利用分钟-公里级分辨率资料,采用双偏振雷达定量降水估计和定量识别中涡旋(MV)的方法,分析2020年5月21日夜间至22日清晨珠三角地区致灾特大暴雨的多尺度特征与机制。结果表明:该事件8 h累积降水最大397 mm,48站次录得>75 mm/h极端小时降雨(EXHP);在天气尺度低空切变线及其南侧强劲的暖湿西南气流影响下,强降水对流的入流空气的CAPE约3000 J/kg,CIN不超过10 J/kg,LCL约300 m,可降水量超过70 mm;降水产生的弱偏北气流和来自热带洋面的偏南气流对峙,形成准静止的中尺度锋区,其抬升作用使对流得以维持;6个低层MV与EXHP伴随,MV强度弱,主要出现在地面中尺度切变线附近,弱冷池的南缘、近地面辐合中心,大多数时刻MV跟逐6 min累积雨量的大值没有空间相关。To increase the awareness of the causes and physical mechanisms of extreme precipitation over monsoon coasts,the disaster-causing extreme precipitation event in the Pearl River Delta from the night of May 21 to the morning of May 22,2020 is analyzed using the km-and-minute resolution data and the dual-polarization radar-based quantitative precipitation estimation and meso-vortex(MV)detection.The results show that,in this event,the maximum 8-hr rain-fall accumulation is 397 mm and there are 48 records of extreme hourly precipitation(EXHP;>75 mm/h)collected by rain gauges.Under the influences of a synoptic low-level shear line and the strong warm,moist southwesterly airflow on its south side,the upstream inflow air fed into the extreme rainfall-producing convective system is characterized by large convective available potential energy(CAPE;about 3000 J/kg),small convection inhibition(CIN)of no more than 10 J/kg,low lifting condensation level(LCL)of about 300 m,and the amount of precipitable water exceeding 70 mm.The precipitation-generated weak northerly flows near the surface converge with the southerly airflow from the tropical o-cean,forming a quasi-stationary mesoscale frontal zone acting as an uplift mechanism to maintain the heavy rainfall-pro-ducing convection.Six meso-γ-scale vortices are accompanied with the EXHP periods.The strength of such meso-scale rotation is generally weak.The mesoscale vortices mostly appear on or near the surface meso-scale shear line and the southern edge of the weak cold pool generated by rain evaporation,collocated with the surface convergence center.The MVs at most times are not spatially related to the large 6 minute rainfall accumulation of the EXHP.

关 键 词:华南前汛期极端降水 多尺度特征 γ-中尺度涡旋 分钟一公里级分辨率观测资料 

分 类 号:P463.1[天文地球—大气科学及气象学]

 

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