Open Access

Introducing localized constraints in global geomagnetic field modelling

Earth, Planets and Space200658:BF03351943

Received: 18 November 2004

Accepted: 25 August 2005

Published: 14 April 2006


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