A Comparison of Global Lithospheric Field Models Derived from Satellite Magnetic Data
Satellite missions over more than three decades, have added immensely to our understanding of the geomagnetic field. Here, we give a comparison of the lithospheric field models, prepared by various workers from POGO, Magsat, Ørsted and CHAMP satellite data. Mapping the global lithospheric anomalies requires careful reductions which include the main field, its secular variation (SV) and corrections for the external magnetospheric and ionospheric contributions to the data recorded by satellite. The discrepancies between the various maps are mainly due to differences in the rigor with which the data is processed, in the selection of the magnetically quiet periods and in the algorithms used to estimate the spherical harmonic coefficients of scalar potential or the total intensity of the field. The models also strongly differ in how the magnetospheric and ionospheric contributions have been detected and eliminated in order to correct the equatorial, mid-latitude and polar latitude data. We plot the anomaly of the total intensity of the field at 450 km altitude (except ALP94 which is at 400 km).
Key wordsPower spectra filtering lithospheric field models
Unable to display preview. Download preview PDF.
- Langel RA (1990) Global magnetic anomaly maps derived from POGO spacecraft data. Phys. Earth Planet. Inter. 62: 208–230.Google Scholar
- Maus S, Rother M, Holme R, Luhr H, Olsen N, Haak V (2002) First CHAMP satellite magnetic data resolve uncertainty about strength of the lithospheric magnetic field. Geophys Res Letts (in press)Google Scholar
- Olsen N (2001) A model of the Geomagnetic Main Field and its Secular Variation for Epoch 2000 Estimated from Ørsted Data. Geophys J Int(in press)Google Scholar
- Sabaka TJ, Olsen N, Langel RA (2000) A comprehensive model of the near-Earth Magnetic Field: Phase 3. NASA/TM-2000–209894, National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, Maryland.Google Scholar