ECMWF极端降水指数对2016年夏季华东地区极端降水预报的检验

Verification of ECMWF extreme precipitation index for extreme precipitation forecast in East China in the summer of 2016

选取2016年6-8月华东地区降水资料,在分析检验欧洲中期天气预报中心(ECMWF)极端天气指数(EFI)与ECMWF降水预报效果的基础上,提出采用EFI的极端降水指数来改进ECMWF高分辨率模式降水预报的方法.结果表明,华东地区6-8月极端降水主要发生在华东沿海和华东中西部地区,在6月份开始增大,6月底达到最大,后又减小,但最大值略有不同,在7月底至8月初达到一个更高的峰值,随后缓慢下降.EFI极端降水指数对2016年6-8月华东地区的历史极端降水95%和99%分位值有一定的预报能力,但对历史极端降水最大值的预报能力相对较差.随着预报时效的增长,预报效果也随之降低.EFI极端降水指数对极端降水预报的ETS评分整体高于ECMWF高分辨率模式降水,并对极端降水最大值也有一定的预报能力.用EFI极端降水指数改进的ECMWF高分辨率模式降水,对华东地区95%和99%分位值极端降水的预报准确率均有不同程度的提高.

Based on an analysis and comparison of the extreme weather forecast index(EFI)of the European center for medium-range weather forecasting(ECMWF)and ECMWF high-resolution model precipitation forecast on extreme precipitation in East China from June to August in 2016,a method was proposed to use EFI to improve the ECMWF high-resolution model precipitation forecast.The results showed that,extreme precipitation mainly occurred in coastal and midwest regions of East China from June to August.It began to increase in June,reaching a maximum at the end of June,and then decreased,but the maximum obtained a higher value between the end of July and start of August.The EFI had a cer-tain forecasting ability for the 95%and 99%values of the extreme precipitation in East China in the summer of 2016,but it performed poorly in forecasting the maximum of extreme precipitation,and the ability of EFI on forecasting was reduced with the increasing of the forecast time.The equitable threat score of ECMWF high-resolution model precipitation was almost lower than EFI,and it was almost impossible to predict the maximum of extreme precipitation.The improved ECMWF high-resolution model precipitation underwent different degrees of improvement for the 95%and 99%values of the extreme precipitation.