日长季节振荡的振幅变化与南方涛动现象

Correlation of Amplitude Change in LOD Seasonal Oscillations with ENSO

本文提出了小波振幅谱的定义 ,给出了其在频域的表达式及频域周期与 Fourier周期之间的线性关系。通过与谐波分析比较 ,证明了小波振幅谱应用的有效性。应用小波振幅谱研究了日长季节振幅变化与南方涛动之间的关系 ,结果表明日长周年振荡的振幅变化与南方涛动的年际变化呈明显负相关 。

This paper puts forward the definition of Wavelet Amplitude Spectrum(WAS) and gives its expression in frequency domain,then solves the linear relation between the WAS frequency in frequency domain and Fourier frequency.Furthermore the comparison between harmonic analysis and WAS method shows that the WAS method is practical.By using WAS method,we analyze relation between the amplitude changes of seasonal Length-of-Day(LOD) and Southern Oscillation Index (SOI) at interannual scale,the result denotes that annual and semi-annual amplitude oscillation are obvious negative and positive correlation with SOI respectively,especially semi-annual part.