Optimal Marine Geoid Determination in the Atlantic Coastal Region of Argentina

Abstract

The determination of an optimal, in terms of resolution and accuracy, marine geoid model for the Atlantic coastal region of Argentina is investigated using satellite altimetry and shipborne gravity data. The altimetric data used are those of the geodetic phase of the ERS 1 mission while marine gravity data have been employed as well to determine a gravimetric geoid solution. Furthermore, the effect of the Quasi-Stationary Sea Surface Topography (QSST) was taken into account in correcting the altimetric Sea Surface Heights (SSHs) to derive geoid undulations. Special emphasis was placed on reducing the effects of the Sea Surface Variability (SSV) on the densely spaced altimetric SSHs with low-pass filtering. The satellite and shipborne data were combined in the spectral domain to improve the accuracy of the altimetric solution close to the coastline and derive a more rigorous solution. The accuracy of the final geoid models is assessed through comparisons with stacked TOPEX/POSEIDON (T/P) SSHs, known for their high precision. From the results achieved it was concluded that an altimetric geoid accurate to about 5–8 cm (1σ) is feasible in some areas, while the gravimetric solution gives poorer results by about 5–6 cm. The combination of satellite and shipborne data with the proposed algorithm improves the accuracy of the gravimetric geoid model by about 2 cm.