四川盆地一次暴雨过程的数值模拟及螺旋度分析

利用常规观测资料、日本气象厅向日葵8号卫星的相当黑体亮度温度（TBB）资料和NCEP/NCAR再分析资料（FNL）,对四川省一次暴雨过程进行了数值模拟及螺旋度诊断分析。结果表明：中高纬度“两脊一槽”环流形势、副热带高压与大陆高压脊叠加形成的“东高西低”形势,为此次暴雨过程提供了有利的背景场条件;四川盆地中多个中尺度云团的发生、发展与暴雨的发生直接相关;中尺度模式（WRF）较好地再现了四川此次暴雨过程;700 hPa垂直螺旋度的正值区可以很好的指示降水落区的位置和移动,垂直螺旋度的高低空配置对揭示对流系统的演变起着至关重要的作用。

Numerical Simulation and Helicity Analysis of a Heavy Rain Process in Sichuan Basin

Numerical simulation and helicity diagnosis analysis were made on a heavy rain in Sichuan Province using conventional observation data, the equivalent blackbody brightness temperature (TBB) data of the Sunflower 8 satellite of the Japan Meteorological Agency, and NCEP/NCAR reanalysis data. The results show that the "two ridges and one trough" and the "high in the east and low in the west" circulation pattern in the mid-high latitudes provide favorable background field conditions for this heavy rain. The occurrence and development of multiple mesoscale cloud clusters in the Sichuan Basin are directly related to the occurrence of heavy rain. The mesoscale model (WRF) well reproduces the heavy rain process in Sichuan. The positive value area of 700 hPa vertical helicity can well indicate the location and movement of the precipitation area. The high and low altitude configuration of vertical helicity plays a vital role in revealing the evolution of the convective system.