摘要
联系当前极端天气预报服务的需求,在最优集合预报(Analog Ensemble, AnEn)的基础上,结合模式输出统计(Model Output Statistics, MOS)方法,设计了2种基于欧洲中期天气预报中心全球确定性预报模式(EC模式)的预报改进方案(方案I、方案II),首先以2016—2018年EC模式预报及其相应的观测值为训练集,对方案I、方案II和AnEn对2019年1月1日—12月31日北京地区364个观测站的极端气温和风速预报的总体效果进行了检验评估,结果显示无论对极端气温(T)还是极端风速(VM),方案I和方案II的预报准确率相比AnEn均有提升,方案II的提升效果更好。然后,按第2、第98百分位数,定义北京地区各站极端低温(Tm)和极端高温(TM)的阈值分别为-22.3℃和38.8℃,方案I和方案II对该地区T的总体预报效果表明,两种方案在AnEn基础上均有明显改进,其平均绝对误差(EMA)分别降低11.90%和21.43%;同理,按第98百分位数,定义北京地区各站VM阈值为20.3 m·s^(-1),方案I、方案II对VM预报的EMA相比AnEn分别降低23.08%和26.52%。最后,对北京地区逐站Tm、TM和VM的预报效果的检验表明,方案I和方案II在AnEn的基础上对T、VM的预报效果均有所改进,94%以上的站点显示方案II对T和VM预报的改进效果更好。另外,T和VM预报准确率空间分布表明,2种改进方案对山区T和VM预报的改进效果优于平原地区。
Upon the current requirement of the extreme weather forecast and service, we developed two improved prediction schemes(that is,scheme I and scheme II) based on the ECMWF-IFS model(EC model) and the model output statistics(MOS) method on the basis of the Anolog Ensemble(AnEn) method. First, taking the EC model forecasts from 2016 to 2018 and their corresponding observations as the training dataset, the overall performance of scheme I, scheme II, and AnEn for the extreme temperature and wind speed in Beijingfrom January 1 to December 31 in 2019 is tested and evaluated against the observations at 364 stations. The results show that the prediction accuracy of scheme I and scheme II is better than that of AnEn for both extreme temperature(T) and wind speed(VM), particularly for scheme II. Second, according to the 2nd and 98th percentiles, the thresholds of extreme low temperature(Tm) and extreme high temperature(TM) at the different stations in Beijing are-22.3 ℃ and 38.8 ℃, respectively. The overall prediction results of scheme I and scheme II for T in this region show that the two schemes are significantly improved compared to AnEn, and their mean absolute errors(EMA) are reduced by 11.90% and 21.43%, respectively. Similarly, according to the 98th percentile, the VMthreshold of each station in Beijing is set at 20.3 m·s^(-1), and the EMAof VMforecast with scheme I and scheme II is reduced by 23.08% and 26.52%, respectively, compared with AnEn. Finally, the prediction results of Tm, TMand VMat each station in Beijing show that scheme I and scheme II have improved in T and VMon the basis of AnEn, and more than 94% of stations show that scheme II has better performance. In addition, the spatial distributions of prediction accuracy of T and VMshow that the two improved schemes have better performance on the prediction of T and VMin the mountainous areas than in the plain areas.
作者
郝翠
张迎新
徐路扬
邢楠
戴翼
李靖
HAO Cui;ZHANG Yingxin;XU Luyang;XING Nan;DAI Yi;LI Jing(Beijing Meteorological Observatory,Beijing 100089)
出处
《暴雨灾害》
2022年第4期467-476,共10页
Torrential Rain and Disasters
基金
国家重点研发计划(2018YFC1507305)
北京市科技计划项目(Z201100005820002)。
