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Are geomagnetic field reversals controlled by turbulence within the Earth's core?

Lookup NU author(s): David Ryan, Dr Graeme Sarson

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Abstract

We consider geomagnetic field reversal sequences from the last 160 Ma, and find the inter-reversal times to be well fit by a lognormal distribution. Such a distribution could arise from 'multiplicative noise' in the underlying geodynamo; and turbulent fluctuations within the core may be expected to provide such noise via the α-effect of dynamo theory. We investigate this mechanism by coupling a low order αω-type dynamo to a shell model of turbulence. This model reproduces field reversals varying in duration from subchrons to superchrons; these are reasonably fit by a lognormal distribution, consistent with the multiplicative noise mechanism proposed. Copyright 2007 by the American Geophysical Union.


Publication metadata

Author(s): Ryan DA, Sarson GR

Publication type: Article

Publication status: Published

Journal: Geophysical Research Letters

Year: 2007

Volume: 34

Issue: 2

ISSN (print): 0094-8276

ISSN (electronic): 1944-8007

Publisher: American Geophysical Union

URL: http://dx.doi.org/10.1029/2006GL028291

DOI: 10.1029/2006GL028291


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