Main field and secular variation candidate models for the 12th IGRF generation after 10 months of Swarm measurements

摘要: We describe the main field and secular variation candidate models for 12th generation of International Geomagnetic Reference Field model. These two are derived from same parent model, in which is extrapolated to epoch 2015.0 using its associated variation. The model exclusively based on measurements acquired by European Space Agency Swarm mission between launch 11/22/2013 09/18/2014. It computed up spherical harmonic degree order 25 field, 13 variation, 2 external field. A selection local time rather than true illumination spacecraft was chosen keep more measurements. Data geomagnetic indices used minimize contributions. Measurements were screened outliers carefully removed. uses magnetic intensity at all latitudes vector equatorward 50° absolute quasi-dipole latitude. second only vertical component measured total computed. This companion offers a slightly better fit compared discussed.We discuss particular quality does not use full underline that this approach may be when partial directional information known. their retrospectively adopted IGRF allows us criticize our own choices.