Determination of the quasi-stationary sea surface topography from a common adjustment of a geodetic and an oceanographic model

• Published in: Harita Dergisi Vol. 73; no. 18 (özel sayı); pp. 235 - 241
• Main Authors: TZİAVOI, I. N, VERGOS, G. S
• Format: Journal Article
• Language: English
• Published: Harita Genel Komutanlığı 2007
• ISSN: 1300-5790

The determination of accurate marine geoid models from satellite altimetry data usually suffers from the absence and/or in-accuracy of appropriate models of the quasi-stationary sea surface topography (QSST). This is the case for the Mediterranean Sea and especially for its eastern part, where global models are in-adequate since: a) The differences between the various solutions exceed the magnitude of the QSST itself and b) they are most commonly in the form of a low-degree spherical harmonics expansion of the QSST, which re-solves wavelengths much longer than the extension of the area under study. From that rationale, the present study focuses on the determination of a QSST model in the eastern part of the Mediterranean Sea, from a geo-detic point of view. This geodetically oriented QSST determination stands upon the simple principle that the quantity under determination can be derived as the difference between a purely altimetric and a purely gravimetric geoid model. From that initial solution an adjusted model is determined from its common adjustment with an oceanographic QSST model computed from in-situ oceanographic data. Finally, the circulation in the area under study is determined by estimating the velocities and the direction of the sea currents.