梅雨锋暴雨预报对分辨率与积云参数化的敏感性  

The sensitivity of the prediction of Meiyu torrential rainfall to model resolution and cumulus parameterization

作　　者：李祥[1] 张立凤 王敬囝 LI Xiang;ZHANG Lifeng;WANG Jingnan(College of Meteorology and Oceanography,National University of Defense Technology,Changsha 4100731)

机构地区：[1]国防科技大学气象海洋学院,长沙4100731

出　　处：《暴雨灾害》2020年第6期637-646,共10页Torrential Rain and Disasters

基　　金：国家自然科学基金项目(41975066,42075053,42005053)。

摘　　要：利用WRF V4.1.3模式和ERA5再分析资料,对2020年7月7日发生在华中地区的一次梅雨锋大暴雨天气过程进行了分析和数值模拟试验,探究了不同垂直和水平分辨率组合对降雨模拟效果的影响,在此基础上考察了3 km水平分辨率时,是否采用积云参数化方案对降雨模拟效果的影响,结果表明:各试验模拟的中低层环流形势、雨团特征、雨带分布基本与实况一致,但不同试验之间也存在一定差异;选定3个降水大值区,分析了逐小时降水演变发现,无论是降水峰值出现时间还是峰值强度,各试验的模拟结果与实况均有较大偏差,其中水平分辨率相同和积云参数化方案相同的试验的结果比较接近;TS、ETS、BS和SAL评分显示,3 km试验的模拟结果总体要优于12 km试验,说明提高模式的水平分辨率可改善降水预报效果;在3 km分辨率时,不考虑积云参数化方案明显降低了预报技巧,且对大暴雨预报的降低程度更大,但对于不同阈值的降水预报,积云参数化方案的影响不同;改变垂直分辨率对预报技巧的影响不如改变水平分辨率和是否使用积云参数化方案显著;3 km水平分辨率的模式中采用积云参数化方案能显著提升对降雨强度的预报技巧。Using WRF V4.1.3 model and ERA5 reanalysis data,analyses and numerical simulation tests were conducted for a weather event of Meiyu front torrential rainfall occurred in central China on 7 July 2020 to explore the effects of the combinations of different vertical and horizontal resolutions on the rainfall simulation.Based on results from the above analyses,then investigations are carried out on whether ap⁃plying cumulus parameterization at a horizontal resolution of 3 km would influence on the simulation of precipitation.The simulated results show that the features of circulation at middle and low levels,characteristics of rain clusters and rainfall distribution largely conform to the actual situations,although there are some differences among different combinations of tests.For the evolution of hourly precipitation at 3 se⁃lected relatively heavy precipitation areas,the simulation results of each simulation test are greatly deviated from the actual situation.Re⁃sults from tests with the same horizontal resolution and cumulus parameterization are closer to each other.According to TS,ETS,BS and SAL scores,the simulation results of the 3 km tests were generally better than those of the 12 km tests,indicating that finer horizontal resolution of the model could improve the precipitation forecasts.Turning off cumulus parameterization at horizontal resolution of 3 km obviously reduc⁃es the forecasting skill,especially for events with the magnitude of heavy rain and above.However,for precipitation prediction with different threshold values,the influence of cumulus parameterization is different.The effect of changing vertical resolution on prediction skills is not as significant as that of changing horizontal resolution and the inclusion of cumulus parameterization.In the 3 km horizontal resolution mod⁃el,the adoption of cumulus parameterization scheme can significantly improve the prediction skill of rainfall intensity.

关 键 词：梅雨锋暴雨 WRF模式 分辨率 积云参数化 降水检验 

分 类 号：P435[天文地球—大气科学及气象学]