The first Antarctic geomagnetic Reference Model (ARM)

Spherical Cap Harmonic Analysis has been applied to obtain a reference model of geomagnetic secular change for Antarctica valid for the last forty years. In this paper, we use the latest available observatory data to update this model and to compare it with the 8th generation IGRF. In addition, the selected set of total field values used for the generation of the Oersted Initial Field Model have been employed together with observatory data to develop the first complete Antarctic Reference Model (ARM). This model improves the fit to the secular variation deduced from observatory data by about 60% relative to IGRF, and the fit to observatory and satellite field data by 8%. The model allows merging data sets taken at different altitudes and epochs in Antarctica, where significant temporal geomagnetic variations occur.