湘中一次特大暴雨的中尺度特征分析

利用NCEP/NCAR、TBB和WRF中小尺度数值预报模式资料,对2009年7月1～2日湖南湘中持续性暴雨过程期间的中尺度对流系统的形成机理进行了分析。结果表明,特大暴雨的形成过程中伴随着强烈的中小尺度对流运动,局部的降水量达到了强对流风暴量级;锋面上中小尺度对流系统向南面运动,是产生这次大暴雨过程的主要影响系统,回波带中具有中尺度天气系统并沿着切变线自北向南滚动更迭,是造成此次大暴雨的直接原因;长时间的辐合对这次暴雨落区的形成具有重要作用,是产生大暴雨的动力条件;持续的暖平流、垂直风切变对暴雨的发生发展和维持具有重要作用。

Mesoscale Analysis of A Torrential Rain in Central Hunan

Using NCEP/NCAR,TBB and WRF mesoscale numerical weather prediction model data,the formation mechanism of mesoscale convective system was analyzed based on the persistent heavy rainfall from 1/2 July 2009 in central of Hunan Province.The results showed that process of torrential rain formation is accompanied with strong mesoscale convective motion.The rainfall in some places reach strong convective storm level.The main influencing system in the heavy rainstorm process is mesoscale convective system of front moving to the south,and the direct reason is that echo with mesoscale weather systems moves to the shear line from north to south rolling and changing.The persistent convergence plays an important role as the dynamic condition on the formation of rainstorm area.Continuous warm advection and vertical wind shear has a dominant effect on rainstorm during the development and maintenance process.