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New model alternatives for improving the representation of the core magnetic field of Antarctica

Published online by Cambridge University Press:  23 March 2006

Luis R. Gaya-Piqué ,
Dhananjay Ravat ,
Angelo De Santis  and
J. Miquel Torta
Luis R. Gaya-Piqué
Affiliation:
Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy Observatori de l’Ebre, CSIC - URL, Horta Alta 38, 43520 Roquetes, Spain current address: UMBC/GEST at NASA/GSFC, Planetary Geodynamics, Code 698, Greenbelt, MD 20771, USAgaya@geomag.gsfc.nasa.gov
Dhananjay Ravat
Affiliation:
Department of Geology 4324, Southern Illinois University Carbondale, Carbondale, IL 62901-4324, USA
Angelo De Santis
Affiliation:
Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy
J. Miquel Torta
Affiliation:
Observatori de l’Ebre, CSIC - URL, Horta Alta 38, 43520 Roquetes, Spain
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Abstract

Use of the International Geomagnetic Reference Field Model (IGRF) to construct magnetic anomaly maps can lead to problems with the accurate determination of magnetic anomalies that are readily apparent at the edges of local or regional magnetic surveys carried out at different epochs. The situation is severe in areas like Antarctica, where ionospheric activity is intense and only a few ground magnetic observatories exist. This makes it difficult to properly separate from ionospheric variations the secular variation of the core magnetic field. We examine two alternatives to the piecewise-continuous IGRF core magnetic field in Antarctica for the last 45 years: the present global Comprehensive Model (CM4) and the new version of the Antarctic Reference Model (ARM). Both these continuous models are better at representing the secular variation in Antarctica than the IGRF. Therefore, their use is recommended for defining the crustal magnetic field of Antarctica (e.g. the next generation of the Antarctic Digital Magnetic Anomaly Map).

Keywords

geomagnetic secular variationIGRFmagnetic anomaliesspherical harmonics
Type
EARTH SCIENCES
Information
Antarctic Science , Volume 18 , Issue 1 , March 2006 , pp. 101 - 109
Copyright
© Antarctic Science Ltd 2006

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