1 National Space Institute, Technical University of Denmark2 Geomagnetism, National Space Institute, Technical University of Denmark
In this paper, we investigate space magnetic gradiometry as a possible path for future exploration of the Earth’s magnetic field with satellites. Synthetic observations of the magnetic field vector and of six elements of the magnetic gradient tensor are calculated for times and positions of a simulated low Earth orbiting satellite. The observations are synthesized from realistic models based upon a combination of the major sources contributing to the Earth’s magnetic field. From those synthetic data, we estimate field models using either the magnetic vector field observations only or the full gradient tensor observations, and compare our estimated models with the known input model. The results indicate that gradient observations improve the determination of primarily the lithospheric field as well as of the high-degree secular variation. In addition, particular combinations of the individual tensor elements for specific ranges of spherical harmonic degree and order are used to derive a model which is compared with the input model in terms of vector and full tensor observations. This comparison shows that a certain combination of tensor elements improves the ability to resolve especially the high-degree lithospheric field.
Geophysical Journal International, 2014, Vol 196, Issue 1, p. 100-110
Magnetic anomalies; Modelling and interpretation; Satellite magnetics