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Modeling core fluid motions and the drift of magnetic field patterns at the CMB by use of topography obtained by seismic inversion

Kohler, Monica D. and Stevenson, David J. (1990) Modeling core fluid motions and the drift of magnetic field patterns at the CMB by use of topography obtained by seismic inversion. Geophysical Research Letters, 17 (10). pp. 1473-1476. ISSN 0094-8276. https://resolver.caltech.edu/CaltechAUTHORS:20130710-091623902

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Abstract

The thermal wind equations, in which the Coriolis force is balanced by pressure gradients and horizontal density gradients rather than by Lorentz forces, are used to describe patterns of magnetic field drift associated with core fluid motions near the core-mantle boundary (CMB). The advection of magnetic field may be due in part to the flow driven by such horizontal temperature gradients, just as East-West air flow is driven by North-South temperature gradients in the Earth's atmosphere. It is argued that this flow may be concentrated in a shell near the CMB, and the horizontal temperature gradients are expected to be directly proportional to horizontal gradients in CMB topography, the lowest harmonics of which are approximately constrained in seismology. Part of the zonal drift is then associated with the 1=2, m=0 harmonic of CMB topography, and anticyclones are attached to topographic highs (thermal highs). Comparison of our derived flow pattern with those determined purely by magnetic field observations provides tentative support for our model.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/GL017i010p01473DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/GL017i010p01473/abstractPublisherArticle
ORCID:
AuthorORCID
Stevenson, David J.0000-0001-9432-7159
Additional Information:© 1990 by the American Geophysical Union. Received: May 2, 1990; accepted June 18, 1990. We thank Jeremy Bloxham for Discussions and Rob Clayton for the use of his computer graphics programs. This work is supported in part by NSF grant EAR-8816268. Contribution number 4872 of the Division of Geological and Planetary Sciences.
Funders:
Funding AgencyGrant Number
NSFEAR-8816268
Subject Keywords:Geomagnetism and Paleomagnetism: General or miscellaneous; Geomagnetism and Paleomagnetism: Spatial variations (all harmonics and anomalies); Seismology: Structure of mantle and core; Tectonophysics: Core processes
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences4872
Issue or Number:10
Record Number:CaltechAUTHORS:20130710-091623902
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130710-091623902
Official Citation:Kohler, M. D. and D. J. Stevenson (1990). "Modeling core fluid motions and the drift of magnetic field patterns at the CMB by use of topography obtained by seismic inversion." Geophysical Research Letters 17(10): 1473-1476.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:39279
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:10 Jul 2013 18:09
Last Modified:03 Oct 2019 05:05

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