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Interpolation of externally-caused magnetic fields over large sparse arrays using Spherical Elementary Current Systems

McLay, S.A.; Beggan, C.D. 2010 Interpolation of externally-caused magnetic fields over large sparse arrays using Spherical Elementary Current Systems. Annales Geophysicae, 28. 1795-1805. 10.5194/angeo-28-1795-2010

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Abstract/Summary

A physically-based technique for interpolating external magnetic field disturbances across large spatial areas can be achieved with the Spherical Elementary Current System (SECS) method using data from ground-based magnetic observatories. The SECS method represents complex electrical current systems as a simple set of equivalent currents placed at a specific height in the ionosphere. The magnetic field recorded at observatories can be used to invert for the electrical currents, which can subsequently be employed to interpolate or extrapolate the magnetic field across a large area. We show that, in addition to the ionospheric currents, inverting for induced subsurface current systems can result in strong improvements to the estimate of the interpolated magnetic field. We investigate the application of the SECS method at mid- to high geomagnetic latitudes using a series of observatory networks to test the performance of the externalfield interpolation over large distances. We demonstrate that relatively few observatories are required to produce an estimate that is better than either assuming no external field change or interpolation using latitudinal weighting of data from two other observatories.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.5194/angeo-28-1795-2010
Programmes: BGS Programmes 2010 > Earth hazards and systems
ISSN: 0992-7689
Additional Information. Not used in RCUK Gateway to Research.: Geomagnetism and paleomagnetism (Rapid time variations) – Ionosphere (Electric fields and currents; Modeling and forecasting)
NORA Subject Terms: Earth Sciences
Date made live: 14 Oct 2010 16:06
URI: http://nora.nerc.ac.uk/id/eprint/11519

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