Earth magnetic field modeling from Oersted and Champ data

J. L. Le Mouël (1) , P. Shebalin , A. Khokhlov

1 IPGP - Institut de Physique du Globe de Paris

We present a method to model geomagnetic field requiring only a restricted number of measurements on magnetic survey satellite orbits. These points are chosen in an optimal—or close to optimal—manner relying on recent developments in the problem of numerical integration over spheres. The method allows us to compute a series of models at short time intervals, namely 10 days in the present study. At each of these close dates several models are computed from independent sets of data; their redundancy in turn provides a control of results thanks to which the selection of data—for example, as a function of magnetic activity or latitude—may be reduced. We find that the internal low degree Gauss coefficients derived from Oersted and Champ data, respectively, differ from one another by 1 or 2 nT. We then take as a second example of the method application a brief study of the so-called external field. We compare the first-degree axisymmetric field with the D _st index.

Mots clés: Geomagnetic field model; satellite; numerical integration over spheres

Domaines: Planète et Univers [physics]

J. L. Le Mouël, P. Shebalin, A. Khokhlov. Earth magnetic field modeling from Oersted and Champ data. Earth Planets and Space, 2010, 62, pp.277-286. ⟨10.5047/eps.2009.11.003⟩. ⟨insu-03605342⟩