| DOI: | 10.1038/s41561-020-0589-y
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| 论文题名: | Weak magnetic field changes over the Pacific due to high conductance in lowermost mantle |
| 作者: | Dumberry M.; More C.
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| 刊名: | Nature Geoscience
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| ISSN: | 17520894
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| 出版年: | 2020
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| 卷: | 13, 期:7 | | 起始页码: | 516
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| 结束页码: | 520
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| 语种: | 英语
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| 英文关键词: | core-mantle boundary
; electromagnetic method
; lower mantle
; magnetic field
; numerical model
; outer core
; temporal variation
; Pacific Ocean
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| 英文摘要: | For the past few centuries, the temporal variation in Earth’s magnetic field in the Pacific region has been anomalously low. The reason for this is tied to large-scale flows in the liquid outer core near the core–mantle boundary, which are weaker under the Pacific and feature a planetary-scale gyre that is eccentric and broadly avoids this region. However, what regulates this type of flow morphology is unknown. Here we present results from a numerical model of the dynamics in Earth’s core that includes electromagnetic coupling with a non-uniform conducting layer at the base of the mantle. We show that when the conductance of this layer is higher under the Pacific than elsewhere, the larger electromagnetic drag force weakens the local core flows and deflects the flow of the planetary gyre away from the Pacific. The nature of the lowermost mantle conductance remains unclear, but stratified core fluid trapped within topographic undulations of the core–mantle boundary is a possible explanation. © 2020, The Author(s), under exclusive licence to Springer Nature Limited. |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/169581
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| Appears in Collections: | 气候变化与战略
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作者单位: | Department of Physics, University of Alberta, Edmonton, AB, Canada
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| Recommended Citation: | |
Dumberry M.,More C.. Weak magnetic field changes over the Pacific due to high conductance in lowermost mantle[J]. Nature Geoscience,2020-01-01,13(7)
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