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首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >A 6-year westward rotary motion in the Earth: Detection and possible MICG coupling mechanism
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A 6-year westward rotary motion in the Earth: Detection and possible MICG coupling mechanism

机译：地球中6年的向西旋转运动：检测和可能的MICG耦合机构

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Seeking geophysical explanations for the periodic similar to six-year oscillation (SYO) previously found in the Earth's length-of-day variation (Delta LOD), 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 (Y-22). 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 Y-22 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 Delta LOD. 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. (C) 2018 Elsevier B.V. All rights reserved.
机译：寻求与先前发现的六年振荡（SYO）在地球上的六年振荡（SYO）的地球物理解释（Delta LOD），我们使用OSE的阵列处理技术分析全球GPS位移和地磁数据（最佳序列估计），并找到6 yr信号的清晰证据，该信号显现为等级-2阶-2（y-22）的扇形球形谐波图案的向西旋转传播波。基于该时段，空间模式和幅度以及在三个数据集中表现出一致的同步性的估计阶段，我们提出了以下情景：地幔内芯重力（MICG）耦合产生了6倍轴向扭转由扇形Y-22密度异常控制的内芯或赤道椭圆形，在内芯和（下）披露中，在达达拉港的锡播之间的角动量交换中的角色交换。它力地将压力波-2在6 yr中循环通过流体外部核心，这反过来产生相应的GPS和地磁变化。我们的研究结果提供了深层地球动态的洞察力，并证实了较低地幔大型低剪切速度省份的阳性密度异常。 （c）2018年elestvier b.v.保留所有权利。

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