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  • Article
  • Open Access

Introducing localized constraints in global geomagnetic field modelling

Earth, Planets and Space200658:BF03351943

  • Received: 18 November 2004
  • Accepted: 25 August 2005
  • Published:


A set of functions is defined that can be used for modelling the internal part of the geomagnetic field. These functions are represented in term of spherical harmonics of a given maximum degree L and are centred at specific latitudes and longitudes. The number of functions needed and the positions of their centres are such that any potential field of maximum spherical harmonic degree L can be modelled. Formulae are obtained to transform between the potential field representation using these functions and a classic spherical harmonic representation. The shape of these functions can be optimized to make them reasonably localized, and from there it is shown how a localized constraint can be applied to an internal geomagnetic field model. The technique is demonstrated by means of models built from a few months of the Swarm mission synthetic data set.

Key words

  • Geomagnetism
  • Geomagnetic Field
  • Swarm
  • Localized constraints
  • wavelets