南方涛动(SO)与北大西洋涛动(NAO)百年变化特征的正交小波分析
ORTHOGONAL WAVELET ANALYSIS OF SO AND NAO
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摘要: 用正交小波变换方法分析了近121年来季节的南方涛动指数与北大西洋涛动指数的演变特征,结果表明南方涛动指数(SOI)最显著的变化是周期约为2～7年的年际变化,它们的方差贡献率为55.1%。1920年以前和1960年以后SO年际及年代际变化较强,其余时段较弱。而NAOI最明显的变化是周期在2年以下的变化,方差贡献率为64.3%。近百年NAOI年际及年代际变化有减弱趋势。近百年来SOI有-0.52/百年的减小趋势,而NAOI有0.25/百年的增大趋势。SOI与NAOI的气候基本态之间有显著的负相关,在年代际和年尺度变化上它们相关不明显。近期北半球处于SOI低基本态高年际及年代际变率,NAOI高基本态低年际及年代际变率的慢变过程下。Abstract: 12-years (1873～1993) seasonal time series of SOI and NAOI are analyzed by means of orthogonal wavelet transform. It shows that the most significant variation of SOI(NAOI) is in the 2～7-yr(<2-yr) band of period,with 55.1%(64.3%) of variability. Interannual and decadal changes of SOI are more distinct before 1920 and after 1960 than in the other period. In the past century and more,SOI (NAOI) dropped (arised) with a trend rate of -0.52(0.25)/century. SOI manifestly negatively correlated with NAOI only in >28-yr band. Recently northern global climate was controlled by high (low) base state,low (high) decadal and interannual variability of SOI(NAOI).
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Key words:
- SOI /
- NAOI /
- climatic base state /
- orthogonal wavelet transform /
- climatic variabili
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