Are geomagnetic field reversals controlled by turbulence within the Earth's core?
- 27 January 2007
- journal article
- Published by American Geophysical Union (AGU) in Geophysical Research Letters
- Vol. 34 (2)
- https://doi.org/10.1029/2006gl028291
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 theα‐effect of dynamo theory. We investigate this mechanism by coupling a low orderαω‐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.Keywords
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