一次寒潮过程的多种相态降水机理分析

Mechanism Analysis of Multiphase Precipitation during a Cold Wave Process

利用气象站观测资料、NCEP分析资料和中尺度模式WRF—V3，从环流形势、动力机制、温湿特征等方面对2010年2月9—11日江苏一次雨、雪、冻雨、冰雹等不同相态的寒潮过程进行分析。结果表明，冻雨和雪的大气层结有明显差异，冻雨发生时在对流层中低层有融化层，融化层内温度为1～2℃，近地面气温低于0℃；降雪发生时，整层大气温度都在0℃以下。对流层中低层大量的水汽平流和暖平流是造成冬季对流性天气的主要原因，冬季产生冰雹的“高架雷暴”位于近地面冷池之上，冰雹出现前对流层中上层有干空气侵入。WRF—V3模式数值模拟结果表明，降雨和冻雨出现时对流层低层都有雨滴存在，降雪时对流层低层的雨滴消失。

Using the observation data, the NCEP analysis data and the WRF-V3 model simulation results, the multiple weather phenomenon of rain, snow, freezing rain and hail are analyzed from the atmospheric circula- tion, dynamic mechanism, temperature and humidity characteristic etc in Jiangsu Province on 9 - 11 February 2010. The results show that： There are significant differences in atmospheric stratification of freezing rain and snow. The freezing rain occurs in the middle-lower troposphere with melt layer, Temperature in the melt layer is about 1 -2~C, and the surface temperature is below 0~C. When the snowfall occurred, the whole atmospheric temperature is below 0~（2. The main reason for severe convective weather in winter is the severe vapor advection and temperature advection in the middle-lower troposphere. Before the hail appearing, dry and cold air penetrates the upper troposphere above the surface cold pool. The simulation from WRF show that, with the appearance of rain and freezing rain, rain drops exist in the lower troposphere and disappear when it become snow.