GOCE Downward Continuation to the Earth’s Surface and Improvements to Local Geoid Modeling by FFT and LSC

One of the main applications gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite data is their combination with local anomalies for geoid modeling purposes. The aim present paper was determination an improved model wider Hellenic area, using original GOCE SGG filtered to retain only useful signals inside measurement bandwidth (MBW) satellite. SGGs, originally at altitude, were projected a mean orbit (MO) then downward continued Earth’s surface (ES) in order be combined anomalies. For projection MO, grids disturbing gradients from global geopotential (GGM) used, computed per 1 km maximum altitude that MO. continuation process undertaken iterative Monte Carlo (MC) simulated annealing method GGM on ES used as ground truth data. final over area estimated, employing remove–compute–restore both Fast Fourier Transform (FFT) Least Squares Collocation (LSC). Gravity-only, GOCE-only models determined evaluation results carried out against available GNSS/levelling study area. From achieved, it concluded even when FFT so grid improvements differences regarding by 14.53% 27.78% can achieved. LSC focused three different areas Greece, characteristics topography variability. these results, 14.73%, well-surveyed Thessaly, 32.88%, mountainous Pindos, 57.10% island Crete found.