WRF模式不同微物理过程对东北降水相态预报的影响

Impact of different microphysical processes of WRF model on precipitation phase forecasting in Northeast China

为了研究不同微物理过程对中尺度模式降水相态预报的影响,利用中尺度模式WRF(V3.1)和NCEP再分析资料,采用WSM 6方案、Goddard方案和New Thompson方案等3种不同微物理过程参数化方案,对2006—2008年东北地区存在降水相变的11次降水过程进行敏感性试验。通过对降水和云微物理特征影响进行分析,了解不同方案间的预报差异。结果表明:不同微物理方案对降水落区和降水强度预报影响不明显,而降水相态对微物理参数化方案较敏感,主要表现在对雨区和雨夹雪区预报影响显著。从总体预报效果来看,Goddard方案预报效果较好。选用不同微物理参数化方案模拟的底层大气云微物理特征存在较大的差别,这种差别直接导致3种方案间降水相态预报的差异。

In order to study the impact of different microphysical processes of WRF model on precipitation phase forecasting,1 1 precipitation processes with precipitation phase change in the Northeast China from 2006 to 2008 were simulated based on WRF V3.1 and NCEP reanalysis data.Studies were carried out by three microphysical schemes,i.e.a WSM 6 scheme,a Goddard scheme and a New Thompson scheme.According to analysis of precip-itation phase and cloud microphysical characteristics,forecast differences existed in the different schemes were ob-tained.The results show that effects of different microphysical schemes on precipitation falling area and precipitati-on intensity are not significant,while precipitation phase is sensitive to microphysical schemes,especially for fore-casting of falling area of rain and sleet.The Goddard scheme is the best among all schemes according to results of overall forecast.The simulated cloud microphysical features of atmosphere in the bottom layer have significant differences among three schemes,which lead directly to the difference of precipitation phase forecast.