提取准双周和准一月低频振荡的Lanczos滤波器及其应用  

Lanczos filter suitable for filtering quasi-two-week and quasi-one-month oscillations and its applications

作　　者：姚菊香[1] 李丽平[1] 罗璇[1] 杨玮[1] 王盘兴[1] 

机构地区：[1]南京信息工程大学大气科学学院,江苏南京210044

出　　处：《大气科学学报》2012年第2期221-228,共8页Transactions of Atmospheric Sciences

基　　金：江苏省普通高校研究生科研创新计划(CXZZ11_0608);国家自然科学基金资助项目(40633018);江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：根据青藏高原大气热源季内振荡分析的实际需要,设计了适于提取准双周(10～20d)、准一月(20～40d)振荡的Lanczos滤波器(L.f.)。通过与Butterworth滤波器(B.f.)滤波效果的定量分析,确定了准双周、准一月L.f.窗宽参数l的临界值l0分别为24、46;当l≥l0时,L.f.滤波器性能全面优于B.f.。选用拉萨附近格点(90°E,30°N)的1950—2006年整层大气热源资料做了应用试验,结果表明,由l=121的L.f.得到的拉萨夏季准双周、准一月振荡分量质量可靠,可用于青藏高原大气热源季内振荡强度的年际差异和季内过程分析。For the actual demand of analyzing intraseasonal oscillation of atmospheric heat source over the Tibetan Plateau,this paper devises Lanczos filter suitable for filtering quasi-two-week（10—20 d） and quasi-one-month（20—40 d） oscillations.By using the quantitative analysis and comparing with the filtering effect of Butterworth filter,the critical values l0 of window width parameter l of quasi-two week and quasi-one month Lanczos filter are determined as 24 and 46,respectively.The filtering capability of Lanczos filter is better than that of Butterworth filter when l is greater than or equal to l0.The whole atmospheric heat source data of the grid point（30°N,90°E） near Lhasa from 1950 to 2006 are used for test.Results indicate that,filtered by Lanczos filter with its parameter l being equal to 121,the quasi-two week and the quasi-one month components are dependable and can be used to analyze interannual difference and intraseasonal process of intraseasonal oscillation intensity of atmospheric heat source over the Tibetan Plateau.

关 键 词：准双周振荡 准一月振荡 Lanczos滤波器 BUTTERWORTH滤波器 

分 类 号：P433[天文地球—大气科学及气象学]