DOI: 10.1016/j.epsl.2018.05.009
Scopus记录号: 2-s2.0-85047225442
论文题名: A 6-year westward rotary motion in the Earth: Detection and possible MICG coupling mechanism
作者: Ding H. ; Chao B.F.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 495 起始页码: 50
结束页码: 55
语种: 英语
英文关键词: Earth rotation
; geodetic observations
; inner core oscillation
; six year oscillation
; the mantle-inner core gravitational coupling
Scopus关键词: Array processing
; Geodetic satellites
; Geomagnetism
; Coupling mechanism
; Earth rotation
; Geodetic observation
; Geomagnetic variation
; Inner core
; Processing technique
; six year oscillation
; Spherical harmonics
; Shear flow
; angular momentum
; core-mantle boundary
; data set
; detection method
; Earth rotation
; geodesy
; inner core
; lower mantle
; oscillation
英文摘要: Seeking geophysical explanations for the periodic ∼six-year oscillation (SYO) previously found in the Earth's length-of-day variation (ΔLOD), we analyze the global GPS displacement and geomagnetic data using the array processing technique of OSE (Optimal Sequence Estimation), and find clear evidences of the 6-yr signals which manifest as a westward rotary propagating wave of the sectoral spherical-harmonic pattern of degree-2 order-2 (Y22). Based on the period, the spatial pattern, and the amplitudes and the estimated phases that exhibit consistent synchronicity among the three datasets, we propose the following scenario: The mantle-inner core gravitational (MICG) coupling gives rise to a 6-yr axial torsional libration of the inner core controlled by the sectoral Y22 density anomalies, or the equatorial ellipticities, in the inner core and the (lower) mantle, the angular momentum exchange between which manifests as the SYO in ΔLOD. It forces into action a pressure wave-2 cyclic in 6 yr through the fluid outer core, which in turn produces the corresponding GPS and geomagnetic variations. Our findings provide insight into the dynamics of the deep Earth, and corroborate a positive density anomaly for the lower-mantle Large Low-Shear-Velocity Provinces. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109834
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Geophysics, School of Geodesy and Geomatics, Wuhan University, Wuhan, China; Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan
Recommended Citation:
Ding H.,Chao B.F.. A 6-year westward rotary motion in the Earth: Detection and possible MICG coupling mechanism[J]. Earth and Planetary Science Letters,2018-01-01,495