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

Abstract

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 crustmantleboundary, 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 GOCEgradiometric data. More specifically, through the established forward gravity field modelling techniques one can relate the computedcrustal signal in terms of selected second order derivatives with the corresponding observed signal at GOCE altitude, as this is capturedby the gradiometer Level 1b readings. This should permit the band-limited investigation of the observed GOCE signal and hopefully theidentification of selected spectral ranges with a distinct geophysical relation. The presented analysis leads to the construction of a pointwise algorithm, which although tedious and time consuming, provides the evaluation of layer wise crustal contributions at arbitrary spacepoints.

Keywords

• global crustal databases
• gravity signal
• satellite altitude