地球极移振幅和相位的长期变化特征及预测研究

Long-Term Changes of the Amplitude and Phase of the Earth’s Polar Motion and Their Projections

  • 摘要: 利用来自国际地球自转参数服务局(International Earth Rotation Service,IERS)的1900—2013年极移数据,计算其振幅和相位序列,基于EMD(empirical mode decomposition)和LS-SVM(least squares support vector machines)方法,分析了极移振幅和相位的长期多时间尺度变化特征,并预测了极移的未来走向。结果表明:极移振幅变化在1900—2013年主要以增加趋势和6.2a的周期为主,而极移相位变化主要以趋势和低频变化为主;采用EMD对原始信号进行分解,对得到的一系列分量进行LS-SVM建模预测,对极移振幅和相位的预测是有效的;未来极移振幅将进一步加大,地极存在向约68°W的长期漂移趋势。

     

    Abstract: The amplitude and phase time-series of polar motion were calculated by using the polar motion data in 1900-2013, which were provided by the International Earth Rotation Service (IERS). Based on EMD (empirical mode decomposition) and LS-SVM (least squares support vector machines) methods, the long-term changes characteristic of pole motion’s amplitude and phase over multiple time scales were analyzed, and the future projections of polar motion were predicted. The results show that: 1) The amplitude variations of polar motion have main period of about 6.2-year and an increasing trend for 1900–2013, and the phase variations have a trends and low-frequency oscillations; 2) The EMD and LS-SVM model is very effective in the prediction of amplitude and phase variations of polar motion; (3) Polar motion amplitude is further increasing in the future, the trend of the phase has the direction of approximately 68°W.

     

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