20070708阜阳极端降雨事件的综合分析

使用阜阳多普勒天气雷达、安徽省气象自动观测网、卫星云图等资料,对2007年7月8日发生在阜阳市迎仙镇的一次极端降雨事件进行了综合分析.结果表明,这场特大暴雨是在西太平洋副热带高压向南撤退形势下发生的,大气层结主要表现为强的对流性不稳定,特大暴雨对流云带恰好发生在低层辐舍区、高层辐散区,并且和850 hPa典型的静止锋式切变线相对应;特大暴雨由狭窄而持续强盛的对流性回波带形成.切变线的组织作用使得新生回波单体不断地聚合到回波带中,是维持回波带持续强盛的原因.回波单体移动方向和回波带的走向接近一致造成迎仙持续的强降水.

A Comprehensive Analysis on 20070708 Extreme Precipitation Event in Fuyang

Using the comprehensive information of Fuyang radar echoes,automatic weather observation networks and satellite cloud images,an extreme precipitation event at YingxJan town,Fuyang city on 8th July 2007(20070708)is analyzed.Based on the data from the dense meteorological observation network and the statistical data of radar echoes,the rainstorm facts are first revealed. The synoptic analysis of the event data shows that the rainstorm happened in a southward withdrawal process of the west Pacific sub-tropical high,when the atmospheric temperature stratification was strongly convectively unstable.The convective cloud band producing the torrential rain was vertically in a convergent area at low level in the conjunction of a divergent area aloft,and its location coincided with an 850 hPa shear line of stationary front type;and the rainstorm formed within a nalTow and persistently strong convective echo band.The shear line continuously organized new echo cells into the echo band,thus keeping it strong and persistent for ten hours,and the motion direction of echo cells,approximately consistent with the orientation of the strong echo band,enhanced the precipitation intensity of the rainstorm at Yingxian.