广州逐日降水振荡及其延伸期预报的简谐波模型  

THE OSCILLATION OF GUANGZHOU DAILY PRECIPITATION AND ITS SIMPLE HARMONIC WAVE MODEL FOR EXTENDED-RANGE FORECASTS

作　　者：谷德军[1] 纪忠萍[2] 林爱兰[1] 李春晖[1] 郑彬[1] 

机构地区：[1]中国气象局广州热带海洋气象研究所,广东广州510080 [2]广州中心气象台,广东广州510080

出　　处：《热带气象学报》2013年第6期899-906,共8页Journal of Tropical Meteorology

基　　金：广东省气象局项目(2008A02);广东省气象科技计划项目(200903);公益性行业(气象)专项(GYHY201006018);广东省科技计划项目(2012A030200006)共同资助

摘　　要：利用1951--2010年广州逐日降水资料，采用功率谱、小波变换、Lanczos滤波器和简谐波拟合等方法，研究了广州逐日降水的振荡特征及其延伸期预报方法。结果表明，广州逐日降水振荡主要表现为2～4．1d、8d、13-3d、40～60d和120d变化等5种时间尺度的准周期振荡，其中准单周变化、11～21d、21～80d的季节内振荡具有振幅和周期接近的1～2个振荡周期性循环出现的特征。利用小波变换揭示出近期逐日降水距平5d滤波序列变化的主要周期，采用简谐波拟合的方法建立了广州逐日降水5d滤波序列的延伸期预报模型。对1990-2009年近20年的后报结果分析表明，所建立的延伸期预报简谐波模型除第24d和29d外，前33d的预报值与低通滤波值之间的相关达到0．05的显著性水平。对未来34d降水低频分量极大值的预报与实况低通滤波极大值相差在0～2d的概率最高，可为中期与延伸期降水过程出现时段的预报提供重要参考。The oscillation characteristics of daily precipitation in Guangzhou and an extended-range forecast method are studied using observed data during 1951--2010 and methods of power spectrum, wavelet transform, Lanczos filter and fitness by simple harmonic wave. The precipitation is mainly manifested as five quasi-periodic oscillations with periods of 2-4.1, 8, 13.3, 40-60, and 120 days. Among them, the quasi-weekly oscillation and intraseasonal oscillations of 11-21 and 21-80 days exhibit periodically regular occurrence, evolving with similar amplitude and period in one to two periods. The extended-range forecast model is built with the regression of simple harmonic waves, whose primary periods are revealed with wavelet transform from recent evolution by low-pass filter with a cutting period of 5 days. The results of hindcast from 1990 to 2009 show that the correlation between predictions of 1 to 33 days ahead and observations filtered with low-pass exceeds the 95% significance level except the 24th and 29th days. The possibility is the maximum for the 0-2-day difference between the prediction and low-pass filter observation for the future 34 days. So the forecast model of simple harmonic waves can provide important reference for operational medium-and extended-range forecast of precipitation in Guangzhou.

关 键 词：逐日降水振荡 小波变换 延伸期预报 简谐波模型 

分 类 号：P426.6[天文地球—大气科学及气象学]