Introducing POMME, the POtsdam Magnetic Model of the Earth
Models of the main and external field play a key role in the analysis and interpretation of satellite, airborne, marine and ground magnetic data. Here, we introduce a series of main field models with several new features: (1) External fields are parametrised in SM and GSM coordinate systems, accounting for the geometry of the ring current, the magnetosphere and the solar wind. (2) We use vector data globally, instead of the usual approach of using vector data at low latitudes and scalar data at high latitudes. (3) The angles between CHAMP's star camera and its vector magnetometer are co-estimated in a joint inversion with Ørsted data. (4) The model includes 2nd time derivatives of the magnetic field to account for the non-negligible secular acceleration in the current period of new magnetic satellite data. As inferred from the degree spectrum of the current version POMME-1.4, the secular variation is stable to degree 11 and the secular acceleration to degree 6.
Key wordsgeomagnetic field field models main field
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