江淮地区一次农业致灾龙卷天气成因分析

Analysis of the Causes of a Tornado Process which Caused Agricultural Disaster in Jianghuai Region

利用多普勒雷达资料、NCEP资料和其他常规资料,从天气形势、物理量、雷达特征等方面,对2017年7月2日江淮地区发生的一次龙卷过程进行了分析。结果表明,龙卷发生时,江淮地区处在副热带高压边缘,500hPa位于华北冷涡底部,涡后不断有冷空气南下,700和850hPa均有切变线和急流,地面有辐合线;龙卷产生在中等大小的对流有效位能和强垂直风切变条件下,同时抬升凝结高度较低;龙卷在发生前、发生时在雷达图上都探测到三维相关切变、中气旋和龙卷涡旋特征TVS;龙卷发生前,中气旋提前0.5 h出现,这对估计和预警龙卷有较好的指示意义。

Using Doppler radar data,NCEP data and other conventional data,a tornado process that occurred in Jianghuai region on July 2,2017 was analyzed from the weather situation,physical quantity,radar characteristics,etc..The results showed that at the time of the tornado,the Jianghuai region was on the edge of the subtropical high pressure.500 hPa was located at the bottom of the cold vortex in North China.After the vortex,there was continuous cold air southward.Both the 700 hPa and 850 hPa had shear lines and rapids.There were convergence lines on the ground.The tornado was produced under medium size convective effective potential energy and strong vertical wind shear conditions,while the lifting condensation height was low.Before and at the time of occurrence,the tornado detected three-dimensional correlation shear,Meso-cyclone and TVS characteristics on the Doppler radar map.0.5 h occurred in advance of the cyclone,which had a good indication for estimating and warning the tornado.