Comparison of the modelling of topographic and isostatic masses in the space and the frequency domain for use in satellite gravity gradiometry

Abstract

In terrestrial and airborne gravity field determination the formulae for the gravitational potential and its first order derivatives have been evaluated, while second order derivatives are related to the analysis of upcoming satellite gravity gradiometry missions of GOCE type. Especially there, the reduction of topographic and isostatic effects within the remove-restore concept is important to produce a smooth gravity field suitable for downward continuation. Another application of topographic and isostatic reductions consists in the external calibration of the GOCE gravity gradiometer. Based on two different isostatic models (Airy-Heiskanen, condensation models of Helmert) the topographic-isostatic effects of the second radial derivative of the potential are calculated for a GOCE-like satellite orbit. In the space domain tesseroids modelled by Gauss- Legendre cubature (3D) are used. In this paper, the focus is put on the comparison between the modelling of masses in the space and frequency domain.