Greece (HG2023)
Authors: M. Paraskevas, et al.
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Created: 2023
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Resp: M. Paraskevas
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Description:
The Hellas Geoid 2023 (HG2023) is a high resolution hybrid geoid model, computed by the Hellenic Military Geographical Agency (HMGS/NTUA) in Athens, Greece. The HG2023 model allows a direct transformation between ellipsoidal heights in the terrestrial reference system IGS08, and orthometric heights in the system Hellenic Vertical Datum (Piraeus tide gauge's levelling network). The computation is based on the remove-compute-restore technique with EIGEN 6C4 being used as a reference field. The topographic effects were computed with the RTM reduction scheme employing a 5-meter DTM and 100-meter sea topography model. The input gravity data refer to land and marine gravity anomalies for the wider Hellenic area. A spherical FFT approach with modified Stokes kernels is used for the computation of the gravimetric geoid. Then the alignment to each regional vertical datum is based on precise GNSS observations at benchmarks (3258 measurements were used). The external accuracy of the obtained geoid model was estimated at the level of 6 cm, when compared against collocated GPS/levelling data.
Reference:
M. Paraskevas, N. Papadopoulos, D. Ampatzidis (2023). Geoid model determination for the Hellenic area “Hellas Geoid 2023”. Acta Geodaetica et Geophysica, 58, pp. 345-371. DOI: 10.1007/s40328-023-00416-9
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