辽宁省春季透雨集合预报误差分析

利用2016—2018年4月1日至6月30日三个全球数值预报业务中心（CMA、ECMWF和NCEP）的24 h降水集合预报资料和辽宁省降水观测资料，采用TS评分、预报偏差B、Talagrand分布以及BS评分等方法对辽宁省春季透雨（4—6月）CMA、ECMWF和NCEP三套全球集合预报结果进行对比分析。结果表明：三个集合预报中心的集合预报系统的离散度均具有偏小的特征，Talagrand都呈U型分布，即各集合预报系统对量级较小的降水预报值偏大，空报率高；对量级较大的降水预报能力不足，极值偏小，容易产生降水预报偏差。将各中心的确定性检验结果和概率性检验结果进行对比后发现，ECMWF相比CMA和NCEP的TS评分值更高，预报偏差B值更接近于1，也就是说另外两个预报中心对辽宁省春季透雨预报漏报更为明显。从BS评分值和其分解评分值结果来看，ECMWF优于另外两个预报中心。ECMWF对辽宁省春季透雨预报的结果与实况最为接近，检验结果最好，可在日后的预报服务工作中作为主要参考。

Analysis of ensemble forecast error for spring soakingprecipitation in Liaoning province

Based on the 24 h precipitation ensemble forecast products from three global numerical forecast centers(CMA,ECMWF,and NCEP)and surface precipitation observations in the Liaoning province from April 1 to June 30 from 2016 to 2018 and using Threaten Score,Bias,Talagrand and Brier Score methods,the forecast errors for spring soaking precipitation of the above-mentioned products in corresponding time were compared and analyzed.The results show that the dispersions of the ensemble forecast systems of the three centers are all small and their Talagrand diagrams all have a U-shaped distribution.Specifically,each ensemble forecast system overestimates the small magnitude of precipitation and has a high false alarm,and is incapable in forecasting the large magnitude of precipitation and underestimates the extreme value,which is easy to produce forecast deviation.In addition,by comparing the deterministic and probabilistic test results,it is found that TS value is higher and B values are closer to 1 for ECMWF relative to the other two forecast centers,implying that ECMWF has less false alarms than the other centers for spring soaking precipitation forecast in Liaoning province.Besides,the comparisons on the BS value and its decomposition score value also show that ECMWF is better than the other two centers.In summary,with the spring precipitation forecasts closest to the observations in Liaoning province and the best test results,ECMWF is available for forecast service work in the future as the main reference.