淮安市一次初春冰雹过程分析

Analysis on a Hailing Process at Early Spring in Huaian

利用数值预报产品的诊断、卫星云图以及多普勒雷达资料,从冰雹形成机制、动力及热力条件入手,分析了2010年2月28日淮安市出现的一次初春冰雹过程,从中寻找一些突发灾害性天气过程发生的规律、特点,为今后出现类似的天气过程提供预报依据,积累工作经验。结果表明:前期近地面层迅速回暖,在充足的水汽条件配合下,当大气环流配置产生了一定的触发机制后,容易产生此次罕见的强对流天气过程。有利于冰雹产生的物理机制是位于-25～-10℃等温线之间的对流有效位能(CAPE)值较大,有垂直风切变,0℃层距离地面的高度适中。由于冰雹天气过程生消时间短,危害程度大,因此雷达回波图是短时天气预报的重要工具。经分析,冰雹天气产生时,回波云中存在60 dBz以上的回波单体,而且回波区出现的特征是典型的冰雹回波特征,这是判别有否冰雹天气的重要指标。

According to the diagnosis of numerical forecast products,satellite cloud images and Doppler radar data,the thermodynamics and dynamics related to a hail at early spring in Huaian occurred on February 28,2010 were analyzed in details,the occurrence rules and characteristics of such sudden severe weather were found out,which provided basis and accumulate experiences for forecasting similar weather processes.The rapid temperature rise at surface level,in cooperation with plenty vapor conditions,would produce rare strong convective weather process when contactmg with some trigger mechanism.The physical conditions for producing hail weather were larger CAPE between-10 ℃-25 ℃ isotherm with a vertical wind shear and the moderate height of 0 ℃ level.Since the hail process appeared and disappeared in a short time,but produced great damage,the radar echo analysis was an important means for short-time weather forecast.Through analysis,60dbz and above radar cells existed in the echo cloud during the hail process,the typical radar echo characteristics of single echo were the significant indicator of happening of the hail weather.