Davies, CJ, Stegman, DR and Dumberry, M (2014) The strength of gravitational core-mantle coupling. Geophysical Research Letters, 41 (11). 3786 - 3792. ISSN 0094-8276
Abstract
Gravitational coupling between Earth's core and mantle has been proposed as an explanation for a 6 year variation in the length-of-day (ΔLOD) signal and plays a key role in the possible superrotation of the inner core. Explaining the observations requires that the strength of the coupling, Γ, falls within fairly restrictive bounds; however, the value of Γ is highly uncertain because it depends on the distribution of mass anomalies in the mantle. We estimate Γ from a broad range of viscous mantle flow models with density anomalies inferred from seismic tomography. Requiring models to give a correlation larger than 70% to the surface geoid and match the dynamic core-mantle boundary ellipticity inferred from Earth's nutations, we find that 3 × 10(19)<Γ<2 × 10(20) N m, too small to explain the 6 year ΔLOD signal. This new constraint on Γ has important implications for core-mantle angular momentum transfer and on the preferred mode of inner core convection.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2014, American Geophysical Union. All Rights Reserved. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | core-mantle coupling; inner core rotation; inner core viscosity; variations in length of day |
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) |
Depositing User: | Symplectic Publications |
Date Deposited: | 25 Aug 2015 08:54 |
Last Modified: | 23 Jun 2023 21:46 |
Published Version: | http://dx.doi.org/10.1002/2014GL059836 |
Status: | Published |
Publisher: | American Geophysical Union |
Identification Number: | 10.1002/2014GL059836 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:85232 |