WRF模式不同云参数化方案的暴雨预报能力检验及集成试验

Verification and consensus experiments of rainstorm forecasting using different cloud parameterization schemes in WRF model

利用WRFV3. 6的8种微物理方案和6种积云参数化方案对湖北及其周边地区夏季12次暴雨过程进行回报,分析各种方案对暴雨预报的影响。结果显示,各种方案均能较好地预报出降水过程,但其降水强度和范围存在一定差异。当积云参数化方案为KF方案时,对Lin、WSM6、Thompson、Morrison 2-mom、CAM5. 1、WDM5、WDM6、NSSL 2-mom微物理方案做敏感性试验,发现CAM 5. 1方案优于其他7种微物理方案,M orrison 2-mom次之。当微物理方案为CAM 5. 1时,对KF、BM J、GD、SAS、G3D、Tiedtke积云参数化方案做敏感性试验,发现在不同量级降水预报中,6种积云参数化方案各有优劣。综合考虑,GD、SAS、Tiedtke积云参数化方案优于其他3种方案。在此基础上开展多方案集成试验,结果表明集合平均(ensemble mean,EMN)在一定程度上可以减少预报误差,降低单个成员预报的不确定性。

To evaluate the effect of various schemes on rainstorm forecast in summer in Hubei and its surrounding areas,eight microphysical schemes and six cumulus parameterization schemes of WRFV3.6are used to forecast12rainstorm cases.The results show that the prediction effects of different schemes are not the same on different scales.For the eight microphysical schemes(Lin,WSM6,Thompson,Morrison2-mom,CAM5.1,WDM5,WDM6and NSSL2-mom)and KF cumulus parameterization scheme,combined with TS scores,anomaly correlation coefficient(ACC)and root mean square error(RMSE),it can be concluded that CAM5.1is better than others,followed by Morrison2-mom.Under the condition of CAM5.1,the sensitivity test results of six cumulus parameterization schemes(KF,BMJ,GD,SAS,G3D and Tiedtke)indicate that the six schemes both have advantages and disadvantages in the precipitation prediction of different magnitudes.GD,SAS and Tiedtke are better than the other through synthetical consideration.On these bases,the ensemble forecasting experiments are carried out by the ensemble mean(EMN).The results show that the method can reduce the forecast error and the uncertainty of individual member forecasts.