Livermore, PW orcid.org/0000-0001-7591-6716, Hollerbach, R and Finlay, CC (2017) An accelerating high-latitude jet in Earth's core. Nature Geoscience, 10 (1). pp. 62-68. ISSN 1752-0894
Abstract
Observations of the change in Earth's magnetic field, the secular variation, provide information on the motion of liquid metal within the core that is responsible for its generation. The very latest high-resolution observations from ESA's Swarm satellite mission show intense field change at high-latitude localised in a distinctive circular daisy-chain configuration centred on the north geographic pole. Here we explain this feature with a localised, non-axisymmetric, westwards jet of 420 km width on the tangent cylinder, the cylinder of fluid within the core that is aligned with the rotation axis and tangent to the solid inner core. We find that the jet has increased in magnitude by a factor of three over the period 2000--2016 to about 40 km/yr, and is now much stronger than typical large-scale flows inferred for the core. The current accelerating phase may be a part of a longer term fluctuation of the jet causing both eastwards and westwards movement of magnetic features over historical periods, and may contribute to recent changes in torsional wave activity and the rotation direction of the inner core.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. This is an author produced version of a paper published in Nature Geoscience. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | geomagnetism; core dynamics; fluid jets |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mathematics (Leeds) > Applied Mathematics (Leeds) |
Funding Information: | Funder Grant number NERC NE/G014043/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 23 Nov 2016 09:19 |
Last Modified: | 18 Jul 2017 05:23 |
Published Version: | https://doi.org/10.1038/ngeo2859 |
Status: | Published |
Publisher: | Nature Publishing Group |
Identification Number: | 10.1038/ngeo2859 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:108112 |