On the computation of crustal induced gravitysignal at a typical low Earth orbiter altitude

The recent release of crustal digital databases, which offer in a global unified resolution the structure (geometry) and consistency (density) of a distinct number of layers stretching from the variations of the visible topography and bathymetry (outermost crust) down to the crustmantle boundary, enables the utilization of this information in computing the crustal-induced gravity signal at any arbitrary point in space, thus also at (any) satellite altitude. This provides a flexible modelling tool that can be used in the analysis and interpretation of GOCE gradiometric data. More specifically, through the established forward gravity field modelling techniques one can relate the computed crustal signal in terms of selected second order derivatives with the corresponding observed signal at GOCE altitude, as this is captured by the gradiometer Level 1b readings. This should permit the band-limited investigation of the observed GOCE signal and hopefully the identification of selected spectral ranges with a distinct geophysical relation. The presented analysis leads to the construction of a point wise algorithm, which although tedious and time consuming, provides the evaluation of layer wise crustal contributions at arbitrary space points.