大气科学2017，Vol.41Issue(1)：71-90,20.DOI:10.3878/j.issn.1006-9895.1602.15280
基于BCC CSM模式的中国东部夏季降水预测检验及订正
Verification and Correction of East China Summer Rainfall Prediction Based on BCC CSM Model
摘要
Abstract
Based on the re-forecast data from the second-generation seasonal prediction model of National Climate Center,the model's capability to predict summer rainfall over East China and possible reasons for the forecast errors are investigated.Furthermore,the rainfall forecast skill is improved by the application of downscaling approaches.Results indicate that the model is able to capture the two major modes of spatiotemporal variability of summer rainfall over East China to some extent (i.e.the dipole mode and the uniform-distribution mode).However,forecasts at various lead times show obvious errors in variance contributions of these modes and spatial distributions of anomalies and interannual variations of time coefficients,etc.In addition,although the model can reasonably reproduce variations of large-scale circulation and sea surface temperature (SST),it shows limited skills in forecasting summer rainfall over East China.This is partially due to the model's inability to realistically depict the impacts of circulation systems such as the West Pacific subtropical high,the continental high and the middle-high-latitude blocking high.Influences of SST in the tropical Pacific and Indian Ocean on major rainfall modes over East China are also not well described in the model.Furthermore,in terms of the 500-hPa geopotential height,850-hPa zonal and meridional winds,and SST in reforecasts for 1991-2003,predictors with the closest relationship with East China rainfall are identified on global scale and used to establish the single-factor linear regression,multi-factor stepwise regression,and multiple regression downscaling models for rainfall prediction.These downscaling rainfall prediction models are tested independently using reforecasts for 2004-2013,and significant improvements in the forecast of East China summer rainfall are obtained.For the forecast initialized on June 1,for example,the spatial correlation coefficient between predicted and observed EOF 1 (EOF2) modes increases from 0.12 (0.48) for the original prediction to 0.58 (0.80) for the downscale prediction,and the corresponding temporal correlation coefficient rises from 0.47 (0.15) to 0.80 (0.67).Compared to the original forecasts by the model at other lead times,the downscaling forecast models also significantly enhance the prediction skill of rainfall.关键词
BCC_CSM模式/我国东部夏季降水/模态/预报超前时间/降尺度Key words
BCC_CSM model/East China summer rainfall/Mode/Lead time/Downscaling分类
天文与地球科学引用本文复制引用
郭渠,刘向文,吴统文,程炳岩,李瑞,魏鳞骁..基于BCC CSM模式的中国东部夏季降水预测检验及订正[J].大气科学,2017,41(1):71-90,20.基金项目
国家自然科学基金项目41305057,重庆市前沿与应用基础研究项目cstc2015jcyjA0017,中国气象局关键技术集成与应用面上项目CMAGJ2015M47 （）
National Natural Science Foundation of China (Grant 41305057),Advanced and Applied Basic Research Project of Chongqing (Grant cstc2015jcyjA0017),Key Technology Integration and Application Project of China Meteorological Administration (Grant CMAGJ2015M47) （Grant 41305057）
