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Improving time-dependent parameters of magnetic field models

Hamilton, Brian; Macmillan, Susan; Thomson, Alan; Reay, Derek. 2009 Improving time-dependent parameters of magnetic field models. [Poster] In: Second Swarm International Science Meeting, Potsdam, 24-26 June 2009. (Unpublished)

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Abstract/Summary

An important part of modelling the Earth's magnetic field is to accurately characterise its temporal variation, in particular the secular variation, and secular acceleration. These quantities are sensitive to the data selection and the time-dependent parameterisation and we present modifications to these strategies. When selecting satellite data for magnetic field modelling it is normal practice to use less disturbed data collected when the local time is between certain hours during the night and perhaps additionally when the data are not sunlit. However this approach results in gaps in the temporal data distribution which are likely to compromise the model parameters that depend on time. If the solar zenith angle is also a selection criterion, parameters which depend on location will also be compromised as an annual signal is introduced into the data distribution at high latitudes. Here we strive for a more continuous coverage in time. Rather than eliminating large amounts of data which are normally considered to be too noisy to include in the model, we downweight these data. This builds on work done previously involving small-scale noise.

Item Type: Publication - Conference Item (Poster)
Programmes: BGS Programmes > Seismology and Geomagnetism
NORA Subject Terms: Earth Sciences
Date made live: 25 Oct 2012 16:06
URI: http://nora.nerc.ac.uk/id/eprint/20091

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