基于ECMWF模式的四川夏季强降水订正试验  

Calibration of ECMWF model forecast of summer heavy rainfalls in Sichuan

作　　者：曹萍萍[1,2] 康岚 王佳津[1,2] 范江琳 张琪[1,2] CAO Pingping;KANG Lan;WANG Jiajin;FAN Jianglin;ZHANG Qi(Sichuan Meteorological Observatory,Chengdu 610072;Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province,Chengdu,610072)

机构地区：[1]四川省气象台,成都610072 [2]高原与盆地暴雨旱涝灾害四川省重点实验室,成都610072

出　　处：《暴雨灾害》2020年第1期63-70,共8页Torrential Rain and Disasters

基　　金：2019年度四川省重点实验室科研专项(SCQXKJQN2019005);2018年度四川省重点实验室科研专项(省重实验室2018-重点-06);2017年度四川省重点实验室科研专项(省重实验室2017-重点-01);2017年度中国气象局核心业务发展专项(YBGJXM(2017)1A-9);2019年度中国气象局预报员专项(CMAYBY2019-098)。

摘　　要：利用2016—2018年6—8月四川地面观测降水资料(含加密自动站)及同时段ECMWF模式各要素预报场资料,根据基于“配料法”计算所得出的3 h间隔短时强降水概率预报,统计各格点各个转换概率阈值的次数,探索了一种针对模式24 h累计降水预报的强降水订正方法,并运用该方法对2018年6—8月降水集中时段24—72 h时效ECMWF模式降水预报进行逐日试验检验。试验结果表明:(1)从大雨、暴雨降水量级综合检验指标来看,各时效订正后命中率、漏报率、TS评分均有明显改善,且随着预报时效的延长,各指标数值提高的幅度愈大。空报率虽然0—24 h、24—48 h时效预报有所增加,但空报率增加幅度远小于漏报率减小幅度;(2)从个例检验结果来看,订正后的模式预报相比订正前的预报而言,降水量级明显增加,50 mm以上降水落区预报效果有较大程度提升,尤其是0—24 h时效预报,订正后降水落区分布与实况基本一致。By using the precipitation observations(including the encrypted automatic stations)and the ECMWF forecasts for Sichuan during June to August from 2016-2018,based on the probability forecast of short-time heavy rain every 3h derived by the“ingredients method”,we calculate the times of various transition probability threshold at each grid,and then a method to improve forecast accuracy of heavy rainfall of 24h cumulative precipitation forecast in Sichuan was developed.We then applied it to daily test of ECMWF model precipitation forecast for 24-72 h on the precipitation concentration period from June to August of 2018.The results show that:1)According to the composite experiment indicators of precipitation above 25 and 50mm,the hit rate,missing rate and TS score of each period validity have been significantly improved after the calibration,and with the extension of the period validity,the value of each index has been further increased greatly.Although the false alarm rate increases a bit of 0-24 h and 24-48 h forecast,the increase of false alarm rate is far less than the decrease of missing rate.2)According to the experiment of individual cases,the precipitation value increased significantly,the effect of precipitation area forecast above 50mm is greatly improved,which means that the distribution of precipitation area after the calibration is basically consistent with the actual situation,especially for the 0—24h cumulative precipitation forecast.

关 键 词：ECMWF模式 短时强降水概率 强降水订正 降水检验 

分 类 号：P456.7[天文地球—大气科学及气象学]