国家气候中心多模式解释应用集成预测

摘要

多模式集合和降尺度技术是提升模式预测能力的有效工具。该文对国家气候中心多模式解释应用集成预测（MODES）技术与业务应用现状进行了综合介绍。MODES采用欧洲中期天气预报中心、东京气候中心、美国国家环境预报中心和中国气象局国家气候中心4个气候业务季节预测模式输出场，利用EOF迭代、变形的典型相关分析、最优子集回归和高相关回归集成4种统计降尺度方法以及等权平均、经典超级集合等集成方法进行全国月及季节降水和气温预测。目前对 MODES进行了夏季回报检验和约1年的实时业务应用。回报检验和业务应用表明，MODES对气温有较好的预测能力（月预测平均PS评分为76），对降水有一定预测技巧（月预测平均PS评分为68），具有短期气候预测业务应用价值。%Dynamic model is the dominant tool for the seasonal prediction operation in most climate prediction centers of the world.But now,for any single model,the predictability to seasonal precipitation and tem-perature is quite limited.Therefore,two kinds of techniques (i.e.,multi-model ensemble and downscal-ing)are developed efficiently to access better prediction ability.Multi-model ensemble can reduce model error and then bring higher prediction skills.Meanwhile,as the model predictability of circulation is better than that of precipitation and temperature,downscaling improves the prediction of temperature and precip-itation via regional model or statistic methods. Due to the complex physical mechanism,the seasonal prediction to China climate is much a challenge. China National Climate Center (NCC)develops a new kind of prediction technique combining multi-model ensemble and downscaling.At present,the output variables from four seasonal models from WMO GPCs (inclu-ding ECMWF,TCC,NCEP and NCC)are used as predictors and four statistic downscaling methods (EOF-ITE, BP-CCA,Optical Subset Regression,Regress Ensemble of High Correlation Factors )are used to set prediction model.Every model output and every downscaling method are used so that 16 model-downscaling components are available.Besides,two methods (equal-weighted average,classic super-ensemble)are employed to access the en-semble result,respectively.As an index showing the prediction ability,the mean PS scores are computed for the reforecast of recent five years for every model-downscaling and ensemble component.The component with highest mean PS score is chosen as the best prediction result. In NCC,the Multi-model Downscaling Ensemble Prediction System (MODES)are set up to realize the above ideas and the operational application of monthly and seasonal temperature with precipitation over China.Reforecast and operational application are carried out.The present reforecast and operational appli-cation for seasonal climate indicates that MODES has achieved quite good prediction skills for temperature and also improved precipitation prediction.The real-time application for monthly climate prediction for from September 2012 to July 2013 is assessed with NCC traditional PS methods.For monthly mean tem-perature,MODES holds the mean and median PS score of 76 and 81 ,respectively,showing much good prediction ability.Meanwhile,for the monthly precipitation of MODES,the mean and median PS scores are both 68,higher than mean scores of the operational prediction product of NCC.The reforecast and op-erational application indicate that MODES is a useful tool for the short-term climate operation prediction.