The role of dynamic transport in the formation of the inverted charge structure in a simulated hailstorm  

作　　者：XU Liang Tao ZHANG Yi Jun LIU Heng Yi ZHENG Dong WANG Fei 

机构地区：[1]State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences [2]College of Earth Sciences, University of Chinese Academy of Sciences [3]Laboratory of Lightning Physics and Protection Engineering, Chinese Academy of Meteorological Sciences

出　　处：《Science China Earth Sciences》2016年第7期1414-1426,共13页中国科学（地球科学英文版）

基　　金：supported by the National Key Basic Research and Development Program of China (Grant No. 2014CB441406);the National Natural Science Foundation of China (Grant Nos. 91537209 & 41405005);the Basic Research Fund of Chinese Academy of Meteorological Sciences (Grant No. 2014R017)

摘　　要：The inverted charge structure formation of a hailstorm was investigated using the Advanced Weather Research and Forecasting（WRF-ARW） model coupled with electrification and discharge schemes. Different processes may be responsible for inverted charge structure in different storms and regions.A dynamical-derived mechanism of inverted charge structure formation was confirmed by the numerical model： the inverted structure was formed by strong updraft and downdraft under normal-polarity charging conditions such that the graupel charged negatively in the main charging region in the middle-upper level of the cloud. The simulation results showed the storm presented a normal charge structure before and after hail-fall; while during the hail-fall stage, it showed an inverted charge structure—negative charge region in the upper level of the cloud and a positive charge region in the middle level of the cloud—appearing at the front edge near the strong updraft in the hailstorm. The charging processes between the two particles mainly occurred at the top of the cloud, where the graupel charged negatively and ice crystals positively due to the strong updraft. When the updraft air reached the top of the storm, it would spread to the rear and front. The light ice crystals were transported backward and forward more easily. Meanwhile, the positively charged ice crystals were transported downward by the frontal subsidence, and then a positive charge region formed between the -10°C and -25°C levels. Subsequently, a negative charge region materialized in the upper level of the cloud, and the inverted charge structure formed.The inverted charge structure formation of a hailstorm was investigated using the Advanced Weather Research and Forecasting(WRF-ARW) model coupled with electrification and discharge schemes. Different processes may be responsible for inverted charge structure in different storms and regions. A dynamical-derived mechanism of inverted charge structure formation was confirmed by the numerical model: the inverted structure was formed by strong updraft and downdraft under normal-polarity charging conditions such that the graupel charged negatively in the main charging region in the middle-upper level of the cloud. The simulation results showed the storm presented a normal charge structure before and after hail-fall; while during the hail-fall stage, it showed an inverted charge structure—negative charge region in the upper level of the cloud and a positive charge region in the middle level of the cloud—appearing at the front edge near the strong updraft in the hailstorm. The charging processes between the two particles mainly occurred at the top of the cloud, where the graupel charged negatively and ice crystals positively due to the strong updraft. When the updraft air reached the top of the storm, it would spread to the rear and front. The light ice crystals were transported backward and forward more easily. Meanwhile, the positively charged ice crystals were transported downward by the frontal subsidence, and then a positive charge region formed between the ?10 and ?25°C levels. Subsequently, a negative charge region materialized in the upper level of the cloud, and the inverted charge structure formed.

关 键 词：Severe storm Mesoscale model Inverted charge structure 

分 类 号：P426.64[天文地球—大气科学及气象学] P427.3