“2013.3.19”飑线天气过程分析

Analysis of squall line process on 19th March 2013

利用常规天气图、物理量、多普勒雷达Web GIS拼图、自动站雨量等资料,采用中分析和特征提取方法,对2013年3月19～20日江西出现大范围冰雹的飑线天气过程进行分析,结果表明：本次飑线天气是在多种天气系统相互作用下形成的.出现冰雹的主要原因有较大的不稳定能量累积、500 hPa有干层发展、中低层有强垂直风切变,风向随高度顺转,以及较低的0℃和-20℃高度;未出大风的原因是地面与高空的温差不够,逆温层厚度较厚;未出大范围强降水的原因是湿层厚度不厚、中低层有强风垂直切变、中层异常干,以及cape值偏强.

By using routine synoptic data, physical quantity, Web GIS radar mosaic products, andprecipitation elements from AWS, adopting methods of mesoscale analysis and feature extraction, thesquall line process caused large scale hail storm on 19--20th March 2013 in Jiangxi is analyzed. Theresults show that the interaction of weather system leads to this squall line process. The large unstableenergy,500 hPa dry layer,severe vertical wind shear in low level,wind direction veering with height,low 0 ℃ and --20 ℃ heights cause the hail storm. The reasons why there is no fresh gale are heavethermal inversion layer, low range of temperature between surface and upper air. Thin wet layer,severe vertical wind shear in middle level, unusua｜ dry middle layer and high cape decrease the quantityof heave precipitation.