基于时变关键区和时滞多变量的长江下游10～30d低频降水实时预报  

10 ～ 30 d Extended-range Low Frequency Rainfall Real-time Forecast for Lower Yangtze Region Based on Time-varying Key Area and Multivariable Lagged Regressive Model

作　　者：黄世成[1] 杨秋明[1] 李熠[1] 

机构地区：[1]江苏省气象科学研究所,南京210009

出　　处：《科学技术与工程》2014年第22期1-6,共6页Science Technology and Engineering

基　　金：国家自然科学基金项目(41175082);江苏省气象局开放基金重点项目(201107);沪通铁路长江大桥气象评估项目资助

摘　　要：利用NCEP/NCAR逐日850 hPa再分析风场资料和长江下游地区25站逐日降水资料,采用Butterworth二阶20～30 d滤波,通过变系数时滞回归和关键区自动筛选方法,构建了长江下游地区汛期（5～8月）的延伸期低频降水实时预报模型方案,对1979、2013年的汛期降水分别做了回报和预报试验.结果表明,基于多变量时滞回归方程（MLR）的实时预报方案,能客观地反映影响长江下游夏季强降水的欧亚环流季节内振荡（ISO）传播特性的时间变化,为长江下游地区强降水延伸期预报提供主要信号.提出的实时预测方案中,关键区的选择随建模样本而变化,体现了ISO变化的多样性和一定程度的不稳定性,预测模型能及时适应大气内部动力过程和外部强迫引起的时滞相关结构的改变,在一定程度上提高了延伸期预报的能力。By Using the NCEP/NCAR reanalysis daily 850 hPa wind data and daily precipitation data of 25 weather stations over the lower Yangtze region,based on the 20 ～30 d second-order Butterworth filter and with the varying-coefficient time lagged regression models and rainfall key-area auto filter,an extended-range real-time forecast model solution was established for low frequency rainfall of Yangtze River downsteam in flood season from May to August,and then it was used in hindcast and foecast experiment in the flood season of 1979 and 2013.The results show that the real-time foecasting solutions based on multivariable lagged regressive model （MLR）,can objectively reflect the time-varying propagation characteristics of the intra-seasonal oscillation （ISO） for Eurasian circulation that affect the sevee rainfall over lower Yangtze region during summer,and offer a main signal for the extended-range foecast for strong precipitation over the area.The rainfall key areas change with the modeled samples in the proposed real-time prediction scheme,and have reflected the diversity and a certain degree of instability of ISO changes.The prediction model can promptly adapt to the change of relevant time-lag structure caused by the internal dynamics of atmospheric processes and other external forcing,and have improve the ability of extendedrange forecast to a certain extent.

关 键 词：时滞回归模型 时变关键区 20~30 d低频降水 实时预报 

分 类 号：P456.8[天文地球—大气科学及气象学]