江苏一次突发暴雨的数值模拟

采用中尺度WRF模式（WRF3．4）和WRF-3DVAR系统，同化GTS常规观测资料和GPS反演的探空廓线资料，对2012年8月10日发生在江苏东北部地区的一次突发性特大暴雨进行数值模拟，并利用高分辨率的模式输出数据对此次暴雨过程进行多尺度分析和对流不稳定性研究。结果表明：模拟结果较好地再现了此次过程；台风低压和中纬度槽脊系统相互作用，中低层弱冷空气扩散和高、低空急流耦合为此次暴雨过程提供了有利的大尺度背景；地面中尺度辐合线和迅速发展的β中尺度对流系统（M8CS）是直接导致此次局地突发性暴雨的中尺度系统，地面中尺度辐合线的位置和暴雨的落区基本一致，M8CS的强烈发展对应于暴雨的最强阶段；暴雨发生前和暴雨发生时，对流系统中等日。线密集而陡峭，不稳定能量的突然性释放造成αθ／Oz迅速减小，口。垂直剖面呈伸向低空的“漏斗状”分布，有利于垂直涡度和对流不稳定发展。

Numerical Simulation of a Sudden Rainstorm Process in Jiangsu Province

The torrential rain is simulated with the mesoscale WRF（ WRF 3.4） model and WRF- 3DVAR system on the basis of the GTS conventional observational data and GPS radiosonde data. Using high-resolution model output data, multi-scale analysis and convective instability study is carried. The re- sults show that the simulated result well reproduces this process occurred on the 10th of August, 2012; interaction between typhoon depression and mid-latitude trough system, diffusion of weak cold air in mid and low level, coupling of upper and lower jet provide favorable backgrounds on the large scale circula- tion. The ground mesoscale convergence line and rapidly developing 13 mesoscale convective systems （M~CS） are the direct mesoscale systems of the torrential rain. The location of ground mesoscale conver- gence line and rainstorm area are basically the same; strong development of M~CS corresponds to the storm＇ s most powerful stage; before heavy rain occurred and during the storm, 0o line in convective sys- tem is intensive and steep, the sudden release of instability energy results αθ/z sudden decrease, 0e vertical section is reaching lower funnel-shaped distribution, which are conductive to vertical vorticity and convective instability.