摘要
许多因素可以导致地球自转速度的变化,如地表物质的再分配,地表风对固体地球的摩擦作用,海平面气压(SLP)变化通过山脉对固体地球的推动作用等。因此,地球自转速度也呈现错综复杂的变化。本文将表征地球自转速度变化的日长(LOD)数据分解为多个尺度的波动,包括以13.6 d、27.3 d、0.5 a、1 a为周期的波动以及年际变化和年代际变化。通过分析LOD年际变化与南方涛动指数(SOI)的相关关系,证明了地球自转年际变化主要体现厄尔尼诺/南方涛动(ENSO)信号。在此基础上,通过小波相干分析方法证明了大气角动量(AAM)变化对地球自转速度40 d～5 a周期的波动具有激发作用。
Earth＇s rotation can be changed in several ways,for example,the redistribution of surface mass,the surface wind drag effect and mountain torque caused by Sea Level Pressure（SLP） anomaly.Therefore,earth＇s rotation has complex variations.In this paper,the Length Of Day（LOD） data which indicate the rate of earth＇s rotation were separated to several fluctuations including decadal variations,interannual variations and the fluctuations with periods of 13.6 days,27.3 days,semiannual,annual.The interannual variations of LOD are related to El Nio-Southern Oscillation（ENSO） event according to the high correlation between LOD anomaly and Southern Oscillation Index（SOI）.It was demonstrated that the fluctuations in LOD with periods from 40 days to 5 years（including semiannual,annual and interannual variations） are excited by the Atmospheric Angular Momentum（AAM） variations by using the wavelet coherence analysis.
出处
《海洋环境科学》
CAS
CSCD
北大核心
2013年第3期424-427,共4页
Marine Environmental Science
基金
海洋公益性行业科研专项(201005027-4)
