四种降水融合产品在四川持续性强降水过程中的对比评估

Comparative Assessment of Four Merged Precipitation Products in a Sustained Heavy Rainfall Process in Sichuan

利用四川省地面降水观测资料,针对2020年8月发生在四川的一次持续性强降水过程,采用多种评估指标对国家气象信息中心研发的四种降水融合产品(FAST_5KM、FRT_5KM、RT_1KM、NRT_1KM)进行对比评估。结果表明:对于过程累计降水量,四种融合产品均能很好地反映此次降水过程,1km产品对降水落区的刻画更为细致,和实况有较高一致性,NRT_1KM偏差最小,FAST_5KM差别最大。四种产品的降水中心与实况都略有偏差,1km产品降水中心更接近实况。四种产品小时降水量走势与实况一致,但峰值均低于实况小时降水峰值,1km产品小时雨量更接近实况。对于24h累计降水量,四种降水融合产品均能表征出逐日降水落区的移动,且落区、走向和雨带形态均与实况较为一致,1km产品的雨强和落区更接近实况。对于晴雨准确率,四种产品无雨站点较实况均偏少,1km产品最为接近实况,准确率基本维持在95%。降水融合产品的小时最大雨强与实况均有较好的对应关系,1km产品优于5km产品,FRT_5KM优于FAST_5KM,NRT_1KM最优。综合来看,1km产品优于5km产品,1km近实时产品优于实时产品,5km三源产品优于二源产品。

Based on the surface observed precipitation data in Sichuan Province,aiming at a sustained heavy rainfall process in Sichuan in August 2020,four merged precipitation products(FAST_5KM,FRT_5KM,RT_1KM,NRT_1KM)developed by National Meteorological Information Center were compared and assessed by using various assessment indexes.The results show that,for the accu-mulative precipitation of the process,the four merged products can reflect the precipitation process well,the 1KM products are more de-tailed to describe the rainfall area,and have a high consistency with the actual,the deviation of NRT_1KM is the smallest and FAST_5KM is the biggest.The precipitation cells of the four merged products are slightly different from the actual,and the precipitation cells of 1KM products are closer to the actual.The trend of hourly precipitation of the four merged products is consistent with the actual,but the peak value is lower than the actual hourly precipitation peak value,and the hourly precipitation of 1KM products is closer to the actual.For 24h accumulative precipitation,the four merged precipitation products can represent the daily movement of rainfall area,and the rainfall area,trend and shape of rain band are more consistent with the actual,while the rainfall density and area of 1KM products are closer to the actu-al.For the accuracy of clear-rainy forecast,the rainless stations of the four merged products are less than the actual,the 1KM products are the closest to the actual,and the accuracy is basically maintained at 95%.The hourly maximum rainfall density of merged precipitation products has a good corresponding relationship with the actual,the 1KM products are better than 5KM products,FRT_5KM is better than FAST_5KM,the NRT_1KM is the best.In general,the 1KM products are better than 5KM products,1KM near real-time products are bet-ter than real-time products,and 5KM three-source products are better than two-source products.