2016年5月28日杭州一次强对流天气过程分析

Analysis of Severe Convective Weather Process on May 28,2016

利用常规高空、地面资料和自动站资料等,从天气形势、物理机制等方面入手,分析了杭州地区一次强对流天气过程。结果表明:此次强对流天气过程属于低层暖平流强迫类,在弱动力条件、强热力条件下发生。700 hPa以下为强烈的暖湿平流,对建立热力不稳定起主导作用;925 hPa切变与风速辐合、地面倒槽、小闭合高压提供了动力扰动;中层为弱的上升运动区,400 hPa及以上垂直速度明显;500 hPa以下有较强的位势不稳定;此外,来自南海的充沛水汽输送和低层明显的水汽通量辐合区也是此次暴雨产生的必要条件。

Using conventional high altitude,ground data and automatic station data,a strong convective weather process in Hangzhou was analyzed from the aspects of weather situation and physical mechanism.The results showed that the severe convective weather process belonged to the category of low-level warm advection forcing,which occured under weak dynamic conditions and strong thermal conditions.Strong warm and humid advection below 700 h Pa played a leading role in the establishment of thermal instability;925h Pa shear,wind speed convergence,ground inverted trough and small closed high pressure provide dynamic disturbance.The middle layer was a weak upward movement area,and the vertical velocity at and above 400 hPa is obvious;Below 500 h Pa,there was strong potential instability.In addition,the abundant water vapor transported from the South China Sea and the obvious convergence area of water vapor flux in the lower layer were also the necessary conditions for the rainstorm.