The Earth's Gravitational Field Recovery Based on an Optimal Combination of GRACE and GOCE Satellite Data

Modelling the global gravitational field of the Earth in terms of spherical harmonic coefficients has been performed by a stand-alone inversion of a 4-month set of the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) Satellite Gravity Gradiometry (SGG) data and a 9-month set of the GOCE kinematic orbits, as well as by a combined inversion of the aforementioned data sets and 1-year sets of the Gravity Recovery and Climate Experiment (GRACE) K-Band Ranging (KBR) data and its kinematic orbits. It is shown, in particular, that an incorporation of the GOCE data may lead to a dramatic improvement of the GRACE-based gravity field models. The added value of the GOCE data is primarily attributed to the diagonal components of the SGG gravitational tensor.