High-frequency analysis of Earth gravity fieldmodels based on terrestrial gravity and GPS/levelling data: a case study in Greece

The present study aims at the validation of global gravity field models through numerical investigation in gravity field functionals based on spherical harmonic synthesis of the geopotential models and the analysis of terrestrial data. We examine gravity models produced according to the latest approaches for gravity field recovery based on the principles of the Gravity field and steady-state Ocean Circulation Explorer (GOCE) and Gravity Recovery And Climate Experiment (GRACE) satellite missions. Furthermore, we evaluate the overall spectrum of the ultra-high degree combined gravity models EGM2008 and EIGEN-6C3stat. The terrestrial data consist of gravity and collocated GPS/levelling data in the overall Hellenic region. The software presented here implements the algorithm of spherical harmonic synthesis in a degree-wise cumulative sense. This approach may quantify the band-limited performance of the individual models by monitoring the degree-wise computed functionals against the terrestrial data. The performed degree-wise analysis yields insight in the short-wavelengths of the Earth gravity field as these are expressed by the high degree harmonics.