长江中下游一次暴雪冻雨微物理过程模拟研究

根据NECP1°×1°客观再分析资料和常规观测资料，利用中尺度数值模式WRF对2008年1月25—29日长江中下游暴雪冻雨过程进行了数值模拟，结果表明：WRF模式可以很好地模拟出此次强降雪过程高低空环流形势演变特征以及降水带的分布。分析表明，中层西南急流对暖湿空气的输送以及低层冷空气的持续扩散为暴雪和冻雨的发生提供了很好的温度层结条件。云微物理过程特征分析表明，此次暴雪冻雨过程存在多种云系共同降水，中低空600—850 hpa强逆温层尤其是0 ℃层的存在使得雪、冰晶等冰相粒子融化形成过冷却水，是大范围冻雨形成的必要条件，同时也是区分大范围冻雨暴雪形成的重要条件。

Microphysical process simulation of a snowstorm freezing rain in the middle and lower reaches of the Yangtze River,China

Based on NCEP (1°×1°) reanalysis data and conventional observation data, the snowstorm freezing rain process from 25 to 29 in January 2008 was simulated by WRF model in the middle and lower reaches of the Yangtze River. The results indicate that the evolution characteristics of the upper and lower air circulation and precipitation belt distribution in this process can be simulated well by WRF model. The transportation of warm moist air by middle level southwest jet and persistent diffusion of low level cold air provide the temperature stratification conditions for snowstorm and freezing rain. The analysis on the cloud microphysical process indicates that there is multiple cloud systems precipitation in this process. The strong inversion layer especially 0 ℃ layer from 600 hPa to 850 hPa makes snow and ice phase particles melt into super-cooling water, which results in the large range freezing rain. At the same time, it is the important condition for the large range snowstorm freezing rain formation.