地球科学进展

地球科学进展 >

2021 , Vol. 36 >Issue 5: 461 - 471

DOI: https://doi.org/10.11867/j.issn.1001-8166.2021.027

综述与评述

地球内核平动振荡模研究进展

  • 栾威 ,
  • 申文斌
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  • 1.武汉大学测绘学院地球物理大地测量研究所，湖北 武汉 430079
    2.武汉大学测绘遥感 信息工程国家重点实验室，湖北 武汉 430079
栾威（1991-），男，湖北孝感人，博士后，主要从事地球自由振荡简正模研究. E-mail： luanwei@whu.edu.cn
申文斌（1960-），男，湖北武汉人，教授，主要从事地球简正模理论、时频地学应用以及重力场理论及应用研究.E-mail： wbshen@sgg.whu.edu.cn

收稿日期: 2021-01-02

  修回日期: 2021-03-19

  网络出版日期: 2021-07-02

基金资助

国家自然科学基金项目“大地测量计算机代数分析及可视化研究”(41631072);“地球自由振荡的高精度探测及其对地球3D结构的约束”(41574007)

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Advances in Earth's Inner Core Translational Oscillation Modes

  • Wei LUAN ,
  • Wenbin SHEN
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  • 1.Institute of Geophysical Geodesy，School of Geodesy and Geomatics，Wuhan University，Wuhan 430079，China
    2.State Key Laboratory of Information Engineering in Surveying，Mapping and Remote Sensing，Wuhan University，Wuhan 430079，China
LUAN Wei (1991-), male, Xiaogan City, Hubei Province, Postdoctor. Research areas include normal modes of Earth's free oscillation. E-mail: luanwei@whu.edu.cn
SHEN Wenbin (1960-), male, Wuhan City, Hubei Province, Professor. Research areas include Earth's normal modes, time and frequency applications in geoscience, and gravity theory and applications. E-mail: wbshen@sgg.whu.edu.cn

Received date: 2021-01-02

  Revised date: 2021-03-19

  Online published: 2021-07-02

Supported by

Projected supported by the National Natural Science Foundation of China ''The research on the computer algebra analysis and visualization of geodesy''(41631072);"High-precision detection of Earth's free oscillations and its constraining on the 3D structure of the Earth''(41574007)

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摘要

地球内核平动振荡模，即Slichter模，是地球自由振荡的基本简正模之一，其三重分裂周期是确定地球内外核密度差异的重要物理量，对于约束地球深内部密度结构具有重要研究价值。然而，Slichter模的激发机制、衰减机制以及实际探测结果至今悬而未决，具有极大争议，其本征周期的确定也成为当前基础地球物理学的一个国际性难题。首先，总结了地球内核平动振荡模的基本理论，包括其动力学方程和主要求解理论与数值方法，并概述了在不同地球模型下利用不同求解理论计算的Slichter模理论周期。其次，讨论了Slichter模的激发机制和衰减机制的主要假设与猜想，其中液核一阶压力流可能激发Slichter模至可观测水平。最后，回顾了过去30年国内外利用超导重力数据开展Slichter模三重分裂信号探测的主要研究进展，探讨了关于Slichter模探测的未来可能研究方向，即从激发机制探究、超导重力数据精细预处理和极微弱信号叠积增强3个不同角度研究突破，有望实现Slichter模三重分裂信号的可靠探测。

关键词： 地球内核平动振荡模; 理论周期; 激发机制; 衰减机制; 超导重力探测

本文引用格式

栾威 , 申文斌 . 地球内核平动振荡模研究进展[J]. 地球科学进展, 2021 , 36(5) : 461 -471 . DOI: 10.11867/j.issn.1001-8166.2021.027

Abstract

The Earth's inner core translational oscillation modes， also referred to as Slichter modes， are the basic normal modes of Earth's free oscillation， and the periods of the Slichter triplet are important physical quantities which can be used to determine the density jump across the inner core boundary， and the latter is of great research value to constraining the density structure of the deep interior of the Earth. However， there are not generally accepted conclusions so far about the Slichter modes' excitation mechanism and attenuation mechanism as well as the actual detecting results， which lead to great arguments. Hence， the determination of the eigenperiods has become one of the international challenges in fundamental geophysics. This paper firstly summarizes the basic theories of the Earth's inner core translational oscillation modes， including their dynamic equations and main solving theories and numerical methods， and overviews their theoretical periods under different Earth models using different solving theories. Secondly， the main hypotheses and conjectures about Slichter excitation mechanism and attenuation mechanism are discussed， and thereinto， degree-one surficial pressure flow acting in the core may excite the Slichter modes to an observable level. Finally， we review the research progress in the study of the detections of the Slichter triplet signals using the superconducting gravity data in the past 30 years， and discuss some potential future research subjects about the Slichter triplet detection. Therefore， from three different perspectives including exploration of excitation mechanism， fine preprocessing of superconducting gravity data， stacking and enhancement of extremely weak signals， the research breakthrough is expected to achieve reliable detection of the Slichter triplet signals.

Key words： Earth's inner core translational oscillation modes; Theoretical periods; Excitation mechanism; Attenuation mechanism; Superconducting gravimeter detection

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