基于CRA技术对杭嘉湖地区梅汛期强降水过程的预报检验  

Evaluation of Heavy Precipitation Forecasting in Hangjiahu Area During the Meiyu Period Using the CRA Method

作　　者：陆琛莉[1] 任思婧 姜顺雨 秦亚兰 Lu Chenli;Ren Sijing;Jiang Shunyu;Qin Yalan(Jiaxing Meteorological Office,Jiaxing 314050,Zhejiang,China;Zhejiang Weather Modification Center,Hangzhou 310051,China)

机构地区：[1]嘉兴市气象局,浙江嘉兴314050 [2]浙江省人工影响天气中心,杭州310051

出　　处：《科技通报》2024年第11期19-26,共8页Bulletin of Science and Technology

基　　金：浙江省气象局预报员专项项目(2020YBY13)。

摘　　要：本文根据24 h雨带移动,将杭嘉湖地区梅雨过程分为东移型、发展(北抬)型、少动型和南压型。基于CRA(contiguous rain area)技术对2020年梅汛期EC(european centre for medium-range weather forecasts)模式预报强降水过程进行检验,结果显示:误差主要为位移误差和形态误差,其中东移型和南压型位移误差较大,发展型和少动型以形态误差为主;模式对强降雨预报偏北偏东,以发展型和南压型更明显;预报落区偏差在1.5º内,占比69.2%;落区偏差大于1º时,预报纬向偏差明显,除少动型外,其他三型预报质心均偏东;预报强降雨范围及总雨量与实况相比都偏大;但预报平均雨强60 mm以上和200 mm以上雨量极值时,偏小;预报最大雨量时,发展型偏大,东移型和少动型偏小。对EC、NCEP-GFS模式(national centers for environmental predictionglobal forecast system)和OCF集成预报(optimal consensus forecast)的检验结果:强降雨范围预报总体都偏大;总雨量预报EC和OCF偏大;平均雨强EC和OCF预报与实况相近,NCEP-GFS预报偏小;最大雨量预报都偏小,但高于100 mm时,EC和OCF偏小不明显。According to the 24 h rain band movement,precipitation procedures during the Meiyu period in Hangjiahu area are classified as eastward-moving type,developing type(northward-lifting type),less-moving type and southward-moving type.Evaluation of the EC(european centre for medium-range weather forecasts)model forecasts for the Meiyu period of 2020 using the CRA(contiguous rain area)method leads to the following conclusions;The errors are mainly divided into displacement errors and pattern errors;The displacement errors of the eastward-moving and southward-moving types are larger than other two types,and the errors of developing and less-moving types are dominated by pattern errors;The forecast of heavy precipitation is generally north-easterly,which is more obvious in the developing and south-pressing types;The percentage of forecast position deviation smaller than 1.5ºis 69.2%;When forecast position deviation is greater than 1º,latitudinal error becomes obvious.Forecast for the center of mass is always eastward except the less-moving type;The coverage and intensity of heavy precipitation forecast are larger than the actual situation;However,for the average rainfall greater than 60 mm and extreme values greater than 200 mm,the forecast is smaller than observation;The maximum rainfall forecast is larger than observation for the developing type and smaller than observation for the eastward-moving and less-moving types.Evaluation results of EC,NCEP-GFS(National Centers for Environmental Prediction-global forecast system)model and OCF integrated forecasts(optimal consensus forecast)show the coverage of heavy precipitation in all models are larger than observation;The total rainfall forecast in EC and OCF are both larger than observation;The average rainfall intensity in EC and OCF is similar to the observation,and the NCEP-GFS is smaller;The maximum rainfall forecast in all models are smaller than observation,which is not significant in EC and OCF when the rainfall forecast is higher than 100 mm.

关 键 词：CRA检验 梅汛期强降水 梅雨分型 模式预报 

分 类 号：P457.6[天文地球—大气科学及气象学]