高架雷暴诱发弱对流性暴雨过程分析

Analysis of a Weak Convective Rainstorm Process Induced by Elevated Thunderstorms

从2015年4月7日一次赣北区域性暴雨天气过程出发,分析了过程闪电强度及分布、回波特征、降水强度、天气形势配置、系统垂直结构和物理量特征。结果表明,本次过程是一次高架雷暴诱发的弱对流性暴雨天气过程,闪电强度较弱,次数较少,以积层混合云降水回波为主,回波强度20~40 d BZ,最大降水强度不超过15 mm/h,天气形势配置和系统垂直结构显示明显的高架雷暴特征,主要的水汽、不稳定和抬升条件位于850h Pa以上,相关物理量也主要反映在700 h Pa层次最为明显。春季冷锋后部高架雷暴天气一直是预报业务的难点,本文也尝试总结了该类型天气的预报着眼点。

According to the regional rainstorm in the north of Jiangxi happened on 7th April,2015,we analyzed the lightning intensity and distribution,echo characteristics,precipitation,synoptic situation,vertical system structure and several physical quantities. The result shows that this weak convective rainstorm process was induced by elevated thunderstorms. The lightning intensity was weak and happened not too much. The main echo was only 20 ~ 40 d Bz caused by laminated hybrid cloud. The largest precipitation was lower than 15 mm / h. Characteristics of elevated thunderstorms was obvious in synoptic situation and vertical system structure. The better conditions of water vapor,unstable energy and thermal appeared above 850 h Pa and the related physical quantities were more obvious at700 h Pa layer. Elevated thunderstorms behind cold front in spring are difficult to forecast,so we try to summarize the forecasting index of these processes.