CFSv2在湖北省梅雨特征量延伸期预报中的应用

利用NCEP的气候预报系统第二版(CFSv2)提供的逐日降水模式资料,采用集合预报方法开展区域性夏季降水预报,使用出入梅日期均方根误差(RMSE)、准确率(ACCU),梅雨期长度均方根误差(RMSE)及梅雨雨强距平符号一致率(Pc)等3种方法评估模式资料对湖北省梅雨特征量的预报能力。结果表明:入梅预报提前13 d的ACCU可达0.5以上、RMSE小于3 d,出梅预报提前14 d的ACCU可达0.5以上、RMSE小于3 d,梅雨期长度预报提前14天的RMSE小于5 d,梅雨雨强预报提前14 d的Pc可达0.5以上。梅雨特征量总体预报时效为14 d左右,CFSv2模式资料对区域性夏季降水在梅雨延伸期时段表现出一定的预报技巧。

Application of CFSv2 in extended-range forecast of Meiyu characteristics in Hubei province

Using daily precipitation model data produced by the second version of Climate Forecasting System of NCEP(CFSv2),the ensem ble prediction method is used to carry out regional summer precipitation forecast.Three methods,i.e.,the root mean square error(RMSE)and accuracy(ACCU)of the onset and the ending time of Meiyu,the RMSE of the length of Meiyu,and anomaly sign consistency rate(Pc)of the average rainfall amount of Meiyu,are used to evaluate the forecast ability of the model to the Meiyu characteristics in Hubei province.The re sults show that the onset of Meiyu forecast is 13 days in advance,the ACCU is above 0.5,and the RMSE is less than 3 days.The ending of Meiyu forecast is 14 days in advance,the ACCU is above 0.5,and the RMSE is less than 3 days.The length of Meiyu period forecast is 14 days in advance,and the RMSE is less than 5 days.The average rainfall amount of Meiyu forecast is 14 days in advance,and the Pc is above 0.5.In general,the aging time of Meiyu characteristics forecast is about 14 days.The CFSv2 model shows certain forecast skill for regional summer precipitation during the Meiyu extended-range period.