Ensemble Kalman filter analysis of magnetic field models during the CHAMP-Swarm gap

Beggan, Ciaran D.; Whaler, Kathryn A.. 2018 Ensemble Kalman filter analysis of magnetic field models during the CHAMP-Swarm gap. Physics of the Earth and Planetary Interiors, 281. 103-110. 10.1016/j.pepi.2018.06.002

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Abstract/Summary

Between the de-orbiting of CHAMP in September 2010 and the launch of Swarm in November 2013, there was a lack of satellite vector magnetic field data to use for main field modelling. During this period the difference between field models derived at the time and retrospective analysis (using data both before and after the vector gap) rose to around 20 nT root-mean-square (RMS). We use Ensemble Kalman Filtering (EnKF) to combine models of steady flow at the outer core surface with magnetic field models derived from the period when no vector satellite data were available. Since we find that the field models produced during periods without vector satellite data are just as good as the annual predictions from a flow model, there appears, at present, to be no overall benefit to using EnKF to improve field forecasting. This will remain the case until flow modelling can better forecast secular variation.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.pepi.2018.06.002
ISSN:	0031-9201
Additional Keywords:	Ensemble Kalman filtering Magnetic field modelling Core flows Satellite vector data
NORA Subject Terms:	Earth Sciences
Date made live:	18 Jun 2018 12:09 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/520283

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