气候变化领域集成服务门户(CCPortal): Weak magnetic field changes over the Pacific due to high conductance in lowermost mantle

CCPortal

DOI	10.1038/s41561-020-0589-y
	Weak magnetic field changes over the Pacific due to high conductance in lowermost mantle
	Dumberry M.; More C.
发表日期	2020
ISSN	17520894
起始页码	516
结束页码	520
卷号	13 期号:7
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.
英文关键词	core-mantle boundary; electromagnetic method; lower mantle; magnetic field; numerical model; outer core; temporal variation; Pacific Ocean
语种	英语
来源期刊	Nature Geoscience
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/206764
作者单位	Department of Physics, University of Alberta, Edmonton, AB, Canada
推荐引用方式 GB/T 7714	Dumberry M.,More C.. Weak magnetic field changes over the Pacific due to high conductance in lowermost mantle[J],2020,13(7).
APA	Dumberry M.,&More C..(2020).Weak magnetic field changes over the Pacific due to high conductance in lowermost mantle.Nature Geoscience,13(7).
MLA	Dumberry M.,et al."Weak magnetic field changes over the Pacific due to high conductance in lowermost mantle".Nature Geoscience 13.7(2020).