双参微物理方案对一次强降水过程的数值试验  

A sensitivity experiment of forecasting precipitation with double-moment microphysics schemes in WRF model

作　　者：单云鹏 银燕[1] 肖辉[1] 

机构地区：[1]南京信息工程大学中国气象局气溶胶与云降水重点开放实验室,南京210044

出　　处：《气象科学》2014年第1期1-9,共9页Journal of the Meteorological Sciences

基　　金：国家自然科学基金(41030962);江苏省高校优势学科建设工程资助项目(PAPD)

摘　　要：利用WRF模式,分别采用WDM6和Morrison双参微物理方案对2009年7月23—24日,华东地区的一次强降水过程进行数值模拟。通过对地面累积降水量、降水强度和云中微物理量分析,对比研究了以上两种双参微物理方案对降水的预报效果。结果显示两种方案都低估了强降水区域的降水强度,而且提早预报了降水发生的时间。但相比之下,Morrison方案更接近实际的观测结果,而WDM6方案的误差在50%以上。分析了云中微物理量场和参数化方案计算过程,发现由于WDM6方案对雨滴的定义不合理,在结果中存在大量小粒径的雨滴,使平均粒径远小于典型雨滴,导致雨水的下落过程中,蒸发作用的强度被高估,而沉降过程的强度被低估,因而低估地面降水。A heavy precipitation process in east China during July 23-24, 2009 is simulated to con- duet a sensitivity experiment by WDM6 and Morrison schemes in WRF model. The accumulation precipi- tation, rain intensity and the mierophysical cloud-parameters are analyzed in two simulations to assess the two mierophysies schemes in precipitation prediction. Compared to the observation of the heavy rainfall, the underpredietion of precipitation and the earlier rain starting are simulated by WRF model with both cloud microphysics schemes. However, the precipitation prediction with the Morrison scheme is more rea- sonable, while the WDM6 scheme produced a higher en＇or above 50% compared to the observation. Due to the unreasonable definition of raindrop of WDM6 scheme, more raindrops whose size are smaller than the reasonable raindrop size distribution were modeled. Based on a calculation, it is found that the unrea- sonable definition of raindrops in WDM6 scheme might lead to an overestimation of evaporation and an underestimation of sedimentation for the raindrops, resulting in the underpredietion of accumulated pre- cipitation on the ground.

关 键 词：强降水预报 微物理方案 WRF模式 

分 类 号：P456.7[天文地球—大气科学及气象学]