日长年际变化、El Nino/南方涛动和大气准两年振荡的小波分析

WAVELET ANALYSIS OF INTERANNUAL LENGTH-OF-DAY VARIATION, EL NINO-SOUTHERN OSCILLATION AND ATMOSPHERIC QUASI-BIENNIAL OSCILLATION

本文采用1964-1993年期间日长变化序列、海平面气压和纬向风速资料，通过小波变换等技术研究分析日长年际变化与ElNino／南方涛动、大气准两年振荡之间的关系．结果表明，日长年际变化与ElNino／南方涛动存在着相似的谱结构，而且ElNino／南方涛动叠加上大气准两年振荡后，与日长变化序列的小波变换时频谱更趋于一致．本文研究结果证实，ElNino／南方涛动和大气准两年振荡的贡献基本能够解释地球自转的年际变化．

The length-of-day (LOD) variahon series, an level pressure, and zonal wind sperd data are employed in this paper to make the wavelet analysis of the relationship among interannual LOD variation, El Nino-Southern Oscillation (ENSO) and atmospheric Quasi-Biennial Oscillation(QBO). The results suggest that the inthernnual LOD variation has a spectral stricture similar to that of ENSO. Moreover, the wavelet time-frequency spectrum of ENSO added by atmospheric QBO agrees well with that of interannual LOD variation. The research results of the present paper demonstrate that the contributions of ENSO and atmospheric QBO can generally account for the interannual variation in theEarth' s rotation.