基于CMA-GEPS的延伸期预报能力评估  

Assessment of Extended-Range Prediction Capability Based on CMA-GEPS

作　　者：齐倩倩 朱跃建 陈静[1,2,3] 李晓莉[1,2,3] 田华 汪叶[5] QI Qianqian;ZHU Yuejian;CHEN Jing;LI Xiaoli;TIAN Hua;WANG Ye(CMA Earth System Modeling and Prediction Center(CEMC),Beijing 100081,China;State Key Laboratory of Severe Weather(LaSW),Beijing 100081,China;Key Laboratory of Earth System Modeling and Prediction of China Meteorological Administration,Beijing 100081,China;National Oceanic and Atmospheric Administration(NOAA)/National Weather Service(NWS)/National Centers for Environmental Prediction(NCEP)/Environmental Modeling Center(EMC),College Park,Maryland 20742,USA;School of Mathematics and Statistics,Henan University,Kaifeng,Henan 475004,China)

机构地区：[1]中国气象局地球系统数值预报中心,北京100081 [2]灾害天气国家重点实验室,北京100081 [3]中国气象局地球系统数值预报重点开放实验室,北京100081 [4]美国国家海洋和大气管理局/国家气象局/国家环境预报中心/环境模式中心,美国马里兰州20742 [5]河南大学数学与统计学院,河南开封475004

出　　处：《热带气象学报》2024年第4期557-572,共16页Journal of Tropical Meteorology

基　　金：国家自然科学基金面上项目(42375152);国家自然科学基金青年基金项目(41906022、42105057);中国气象局地球系统数值预报中心青年基金(CEMC-QNJJ-2021005)共同资助。

摘　　要：基于CMA-GEPS系统开展1~35天的延伸期集合预报,并对该系统的延伸期尺度天气进行预报能力评估。结果表明:关于500 hPa位势高度,以距平相关系数(ACC)为表征的集合预报有效天数在北半球和南半球分别为9天和8.7天,且在北半球呈现季节循环特征,即冬(夏)季值高(低),为大气内在性质的表现;定量分析离散度-均方根误差关系表明,集合预报系统比确定性预报在延伸期尺度上可预报性更高,且北半球及南半球的潜在可预报天数分别为18天和16天。关于2 m温度,CMA-GEPS在延伸期尺度上可较好地描述温度场的空间分布特征,其较大的系统偏差主要位于热力强迫显著的高原或沙漠地区。关于MJO,CMA-GEPS对MJO的有效预报技巧达到15天,优于一般的大气模式,说明CMA-GEPS有潜力进一步发展延伸期天气预报。进一步诊断分析表明:CMA-GEPS对MJO预报的强度偏弱,这与CMA-GEPS描述的热带对流系统偏弱有关;传播速度前8天略偏快,8天之后偏慢;CMA-GEPS可较好地预报出MJO东传及北传运动;比较发现,CMA-GEPS对环流信号传播特征的预报优于对流信号,且描述的MJO东传优于北传特征。This study assessed the extended-range prediction capability of the CMA-Global Ensemble Prediction System(CMA-GEPS).Using this system,we conducted 35-day ensemble prediction experiments and evaluated the forecast capability.Results showed that,at the geopotential height of 500hPa,the ACC skills of the extended-range ensemble prediction system were 9 days and 8.7 days in the northern and southern hemispheres,respectively.The ACC skills in the northern hemisphere exhibited a seasonal cycle with higher prediction skills in winter and lower skills in summer,reflecting the inherent atmospheric properties.Quantitative analysis of the spread-root mean square error(RMSE)skill relations revealed that the ensemble forecasting system was more predictive than deterministic prediction on the extended scale.The potential forecast days in the northern and southern hemispheres were 18 and 16 days,respectively.In terms of 2m temperature,CMA-GEPS effectively captured the spatial distribution characteristics of the temperature field on the extended period scale.Further analysis showed that prediction errors for 2m temperature mainly occurred in desert or plateau areas with significant thermal forcing effects.Additionally,CMA-GEPS demonstrated skillful forecasting of the Madden-Julian Oscillation(MJO)with a lead time of 15 days,outperforming other general circulation models.This suggested that CMA-GEPS has the potential to develop extended-range ensemble predictions further.Moreover,analyses revealed that the predicted intensity of MJO was weaker than the analyses,possibly due to a weak tropical convective system.The predicted propagation speed for the first 1-8 days was slightly faster,while the predicted propagation speed of the 9-35 days was slower compared to the analyses.CMA-GEPS effectively predicted the eastward and northward signals of MJO.Furthermore,the prediction of circulation signal propagation characteristics was better than that of convective signal,and MJO eastward propagation characteristics were better predicted th

关 键 词：CMA-GEPS 延伸期天气 集合预报 MJO 预报能力评估 

分 类 号：P435[天文地球—大气科学及气象学]