Application and verification of the spatiotemporal projection model in the extended-range forecast of summer precipitation in Northeast China
Based on the daily precipitation data and the NCEP/NCAR((National Center for Environmental Pre-diction/National Center for Atmospheric Research))atmospheric reanalysis data in Northeast China from 1979 to 2021,the historical rule of low-frequency precipitation in summer in Northeast China was analyzed using rotating empirical orthogonal function decomposition and ensemble empirical mode decomposition,combined with low-fre-quency precipitation and its related atmospheric intra-seasonal oscillation.A spatiotemporal projection model(STPM)was used to forecast the extended period of low frequency precipitation.The results show that there are obvious regional differences of low frequency precipitation in Northeast China,and the period of low frequency precipitation in different regions has obvious inter-annual variation,with the period of 10～40 days as the main and 40～80 days as the secondary.The key signals of low-frequency precipitation forecast from 10 to 40 days are tropi-cal atmospheric intra-seasonal oscillation,Eurasian teleconnection,low-frequency wave train of Silk Road telecon-nection and zonal wind field near the western Pacific Ocean.The low-frequency precipitation forecast signals from 40 to 80 days mainly come from the factor fields around Northeast China.The experiment on the extension period of the low-frequency precipitation of different frequency bands in Northeast China shows that the forecast ability decreases with the increase of advance forecast time.The predicted validity of low-frequency precipitation for 10～40 days is 10 days.The low frequency precipitation of 40～80 days shows a high forecasting skill,and the forecas-ting validity can reach about 30 days.
万方数据
维普
