一次龙卷生成中风暴单体合并和涡旋特征的雷达观测研究

Analysis of Cell Merger and Vortex Signature During Generation of Tornado in Anhui Based on Doppler Radar Observation

本文利用阜阳市多普勒天气雷达CINRAD/SA资料,分析了2008年7月23日发生在安徽省颍上县的龙卷天气过程。结果表明:本次过程中,风暴单体的连续合并对风暴单体迅速增强为超级单体风暴有重要作用。风暴单体的合并和邻近风暴单体之间的相互作用与龙卷的发生在时间和位置上有较明显的相关,说明风暴单体间的合并和相互作用可能对龙卷存在激发作用,这对龙卷预警具有一定的参考价值。在缺省适配参数条件下,雷达系统CINRAD/SA的中气旋(M)产品和龙卷涡旋特征(TVS)产品对龙卷预警有较好的指示作用。如果风暴被同时识别出M和TVS产品,并观测到风暴单体中存在有界弱回波区,则出现龙卷几率更高。

Based on the Fuyang Doppler weather radar data,the tornado that occurred in Yingshang County,Anhui Province on 23 July 2008 is analyzed in detail.It is shown that the storm is intensified rapidly after the continuous merging of storm cells,and becomes a supercell.The merger and interaction between the storm cells may be instructive for tornado warning for they are highly correlated to the time and location of the tornado.The mesocyclone and tornado vortex signature products with default parameters setting in CINRAD/SA radar system are indicative to tornado warning.When the two kinds of products are detected for the same storm simultaneously along with the observed bounded weak echo areas,the probability of tornado becomes even higher.