黄土高原复杂地形区两次冰雹天气过程对比分析

Comparative analysis of two consecutive hail weathers in complex terrain area of loecs plateau

利用气象观测资料、多普勒天气雷达资料以及ERA5逐小时再分析资料,对2020年5月30日和31日甘肃通渭大冰雹天气过程进行对比分析。结果表明:(1)30日为干冰雹过程,而31日是混合型强对流湿冰雹过程;(2)2次过程都在同一低槽发展东移过程中产生,700 hPa影响系统的差别导致中低层水汽和能量条件不同,是2次过程出现干、湿冰雹的主要原因;(3)物理量诊断表明,31日过程能量高,水汽条件好,热力不稳定和对流不稳定度都比30日过程强,因此冰雹直径更大、降水强度更强;(4)在雷达反射率因子图上,2次过程在回波强度、回波面积及垂直结构等方面有明显差异,这对于强对流临近预警的分类识别有较大帮助。

Based on meteorological observation data,Doppler weather radar observation data and ERA5 hourly reanalysis data,the heavy hail weathers in Tongwei County of Gansu Province on May 30 and 31,2020 were analyzed.The results are as follows:(1)The hail process on May 30 was a dry hail process,while the process on May 31 was a mixed strong convection with wet hail process.(2)Both two processes occurred during developing and moving eastward of the same low-trough,and the difference of influence system at 700 hPa led to difference of water vapor and energy conditions in middle and low levels,which was the main reason for occurrence of dry and wet hail.(3)The diagnostic analysis of physical quantities showed that the energy on May 31 was higher,the water vapor condi⁃tion was better,and the static instability and convective instability were stronger than those on May 30,so the hail diameter was larger and precipitation intensity was stronger.(4)On the radar PPI image of reflectivity,the meso-scale characteristics of the two processes were obviously different,which was very helpful for classification and identification of severe convective nearly warning.