2012年新疆喀什一次罕见冰雹天气的中尺度特征

2012年5月23日午后到夜间喀什地区8县市19个乡镇发生了有气象记录以来罕见的大范围冰雹天气过程。本文利用常规观测资料和新疆喀什多普勒天气雷达资料,分析了冰雹发生的中尺度天气特征。结果表明：对流系统为中-γ尺度,下垫面热力不均匀和水汽分布不均匀是此次强对流天气发生的主要原因。冰雹天气热力作用显著,热力参数CAPE和LI值的高低中心与冰雹天气的发生区域对应较好,且CAPE（LI）随时间增大（减小）;弱的垂直风切变、垂直涡度与倾斜涡度发展是造成大范围雹暴的层结特征;线性多单体风暴、低层弱回波区、低层反射率因子高梯度区是主要回波特征,VIL的跃增对新疆喀什冰雹的临近预报有一定指示意义。

Mesoscale Characteristics of a Rare Hailstorm in Kashi of Xinjiang in 2012

A rare and wide range hailstorm weather process happened in 19 towns of 8 counties or cities in Kashi of Xinjiang from afternoon to night on May 23,2012. Based on the conventional observation data and Doppler weather radar data at Kashi of Xinjiang,the mesoscale characteristics of the hailstorm were analyzed. The results showed that the weather system of the hailstorm was the meso- γscale convection system,and the inhomogenous distributions of heat and water vapor on ground were the main causes to produce the strong convection weather. The thermal effect of the hail weather was significant,CAPE of thermal parameter increased linearly with time while LI of thermal parameter decreased with time,and the high value center of CAPE and LI corresponded well to areas of this hailstorm. The weak vertical wind shear,vertical vortex and slanted vortex development（ SVD） were atmospheric stratification characteristics of the hailstorm,and the main characteristics of echo had linear multi- cell storm,low- level weak echo region（ WER）,high gradient region of low- level reflectivity factor. The leaping increase of VIL would give good indications to the short- term forecasting of hailstorm in Kashi.