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Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/6171

Authors: De Santis, A.*
Qamili, E.*
Title: Shannon information of the geomagnetic field for the past 7000 years
Title of journal: Nonlinear Processes in Geophysics
Series/Report no.: 1/17 (2010)
Publisher: EGU - Copernicus Publications
Issue Date: 12-Feb-2010
DOI: 10.5194/npg-17-77-2010
URL: http://www.nonlinear-processes-in-geophysics.net
Keywords: Shannon Information
Geomagnetic Field
Global Geomagnetic Models
Abstract: The present behaviour of the geomagnetic field as expressed by the International Geomagnetic Reference Field (IGRF) deserves special attention when compared with that shown over the past few thousands of years by two paleomagnetic/archeomagnetic models, CALS3K and CALS7K. The application of the Information theory in terms of Shannon Information and K-entropy to these models shows characteristics of an instable geomagnetic field. Although the result is mitigated when we correct the CALS7K model for its typical spectral damping, the present geomagnetic field as represented by IGRF is still rather distinct, at least for the past 4000 years, a result that is further confirmed by the CALS3K model. This is consistent with a significant global critical state started at around 1750, and still present, characterised by significant decays of the geomagnetic dipole, energy and Shannon information and high K-entropy. The details of how these characteristics may develop are not clear, since the present state could move toward an excursion or a geomagnetic polarity reversal, but we cannot exclude the possibility that the “critical” behaviour will become again more “normal”, stopping the apparent trend of the recent geomagnetic field decay.
Appears in Collections:04.05.03. Global and regional models
04.05.02. Geomagnetic field variations and reversals
04.05.05. Main geomagnetic field
Papers Published / Papers in press

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