2013-07-03山西南部区域性大暴雨成因分析

2013-07-03 Southern Regional Causes of Torrential Rain in Shanxi Province

2013-07-03山西南部出现区域性大暴雨,19个县达到暴雨,其中,8个县的降水量≥100 mm,1 h最大雨强达54.6 mm。利用常规气象观测资料、地面加密自动站资料、卫星云图资料、雷达资料对此次区域性大暴雨成因进行分析,结果表明:1此次大暴雨过程发生在两槽一脊、副高稳定、200 hPa反气旋的大尺度环流背景下,超低空急流加强、低层正涡度、强的上升气流是大暴雨发生的环境条件,大暴雨发生在湿区梯度锋上;2大暴雨由午后热对流产生的暴雨云团和中尺度对流系统造成,热对流云团发生在超低空急流左前侧、山西南部中条山、王屋山的迎风坡和喇叭口地形收缩处,地形抬升作用触发热对流;中尺度对流系统由4个对流云团组成,地面中尺度涡旋是中尺度对流系统的主要触发系统。

2013-07-03 emergence of regional heavy rain in southern Shanxi, 19 counties reached the storm, which, eight counties of precipitation ≥100 mm, 1 h maximum rainfall intensity up to 54.6 mm. Using conventional meteorological data, ground station data is automatically encrypted, satellite image data, radar data on the causes of regional heavy rainfall analysis, the results showed that： ①The heavy rain process occurs in two slots a ridge, deputy high stability, 200 hPa anti-under the large-scale circulation background cyclones, low altitude jet stream strengthened, lower positive vorticity, strong updrafts environmental conditions heavy rain occurs, heavy rain occurred in the wet zone gradient peak; ②Storm clouds and heavy rain from the afternoon heat convection generated mesoscale convective systems caused by thermal convection occurs in low altitude clouds rapids left front side of the mountain in southern Shanxi, Wangwushan windward slope and contraction of the bell terrain, terrain uplift trigger thermal convection;mesoscale convective system consists of four convective cloud composition, surface mesoscale convective vortex system is the main trigger system.