Abstract
The Gravity field and steady-state ocean circulation explorer (GOCE) is
part of ESA’s Earth Explorer Program. The satellite carries
magnetometers that control the activity of magnetorquers for navigation
of the satellite but are not dedicated as science instruments. However,
intrinsic steady states of the instruments can be corrected by alignment
and calibration, and artificial perturbations, e.g., from currents, can
be removed by their characterisation correlated to housekeeping data.
The leftover field then shows the natural evolution and variability of
the Earth’s magnetic field. This article describes the pre-processing of
input data as well as calibration and characterisation steps performed
on GOCE magnetic data, using a high precision magnetic field model as
reference. For geomagnetic quiet times, the standard deviation of the
residual is below 13 nT with a median residual of (11.7, 9.6, 10.4) nT
for the three magnetic field components (x,y,z). For validation of the
calibration and characterisation performance, we selected a geomagnetic
storm event in March 2013. GOCE magnetic field data shows good agreement
with results from a ground magnetic observation network. The GOCE
mission overlaps with the dedicated magnetic field satellite mission
CHAMP for a short time at the beginning of 2010, but does not overlap
with the Swarm mission or any other mission flying at low altitude and
carrying high-precision magnetometers. We expect calibrated GOCE
magnetic field data to be useful for lithospheric modelling and filling
the gap between the dedicated geomagnetic missions CHAMP and Swarm.