孙和平^1,2,,
张苗苗¹,
徐建桥¹,
陈晓东¹,
刘清超^1,2
1. 中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室, 武汉 430077
2. 中国科学院大学, 北京 100049

基金项目: 国家重点基础研究（973）计划项目（2014CB845092）和国家自然科学基金（41621091，41674083，41474062，41374084，41574072）联合资助


详细信息

作者简介: 孙和平, 男, 1955年生, 研究员, 博士生导师, 主要从事地球重力场观测、理论模拟、资料处理、干扰改正和地球动力学应用解释等研究.E-mail:heping@asch.whigg.ac.cn

中图分类号: P218

收稿日期:2017-04-10
修回日期:2017-06-01
上线日期:2018-02-05

Etraction and study of the gravity pole tide using EEMD

SUN HePing^1,2,,
ZHANG MiaoMiao¹,
XU JianQiao¹,
CHEN XiaoDong¹,
LIU QingChao^1,2
1. State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Chinese Earthquake Administration, Wuhan 430077, China
2. University of Chinese Academy of Sciences, Beijing 10049, China


MSC: P218

--> Received Date: 10 April 2017
Revised Date: 01 June 2017
Available Online: 05 February 2018


摘要
摘要:重力极潮，即极移引起的重力变化，是地球由于惯性离心力变化导致地球形变的综合反映，其观测和研究有助于了解地球在长周期频段的响应，约束地球形变、地球内部构造和物理参数.区别于以往研究，本文采用了集合经验模态分解方法（Ensemble Empirical Mode Decomposition，EEMD）从全球5个超导重力仪台站连续重力观测资料中提取重力极潮、消除仪器漂移及极潮频段以外的大部分噪声信号，该方法所用的基函数是基于自身信号获得的；在此基础上，利用最小二乘匹配法分离极潮中的周年项和Chandler项，估算Chandler周期的极潮潮汐因子.结果表明，基于EEMD得到的极潮潮汐因子与前人基于其他消除仪器漂移方法（数学模型或小波分析）得到的结果相符合，精度相当，但由于这种方法是自适应的，因此本文结果更能反映实际物理过程.
关键词: 超导重力仪/
EEMD/
重力极潮/
滤波

Abstract:The gravity pole tide, i.e. the polar-motion-induced gravity variations, is the comprehensive reflection of the Earth's deformation caused by the perturbations in the inertial centrifugal force. The observation and study of the gravity pole tide are helpful to understand the Earth's long-period response and to constrain the Earth's deformation, interior structure and physical properties. Different from the previous studies, in this paper the EEMD (Ensemble Empirical Mode Decomposition) method, the basis function of which is derived from the data themselves, is used to process continuous gravity observation data recorded by 5 global superconducting gravimeter to extract the gravity pole tide, to eliminate the instrumental drift and noise outside the pole tidal band; on this basis, the annual and the Chandler wobbles are separated by least-squares fitting a combination of 2 sinusoidal functions with periods of 365.25 and 432 days to the extracted pole tide, and then the gravimetric factors of the pole tide associated with the Chandler wobble are estimated. Our results show that the gravimetric factors of the pole tide associated with the Chandler wobble obtained through EEMD agree with previous results (based on drift models or wavelet approach) and have comparable internal precision. However, considering that the EEMD is an adaptive process, the results in this study can better reflect the real physical process.
Key words:Superconducting gravimeter/
EEMD/
Gravity pole tide/
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