Analysis of GOCE Omission Error and Its Contribution to Vertical Datum Offsets in Greece and Its Islands

摘要

In this paper we evaluate three different geoid models (a pure and an extended satelliteonly model and a local geoid solution) for the mainland of Greece and fourteen of its biggest islands in terms of signal content and applicability for height system unification. By comparing local geoid heights from GPS and spirit levelling with the three geoid models it is possible to make statements about the Earth's gravity signal that is omitted in these models (omission error). In a further step we try to quantify the contribution of the omission error to the height system unification between the investigated islands. It becomes obvious that a satellite-only gravity field model (GOC005S) until degree and order 200 is not sufficient for the mountainous islands of Greece due to an omission error of up to 2 m. The same model with high frequency corrections from EGM08 as well as topography is able to reduce the omission error drastically and shows similar results as for the local geoid model. As an outcome, we can see homogenous omission errors for the smaller islands and in general a high correlation between the size of the island and the amplitudes of the omission error.