Determinación del nivel medio del mar en el mar de Bransfield. Aplicación a la determinación del geoide en islas Decepción y Livingston, Islas Shetland del Sur (Antártida)

Abstract

This work presents a detailed study in order to determine the mean sea level (NMM), the tidal constituents and a precision geoid at Deception and Livingston Islands and the Bransfield Sea area. To carry out these works, it is necessary to define the geodetic reference frame, for this the geodetic networks like REGID (Geodetic network of Deception Island), RENID (Levelling network of Deception Island) and REGRID (Gravimetric network of Deception Island) have been used. In addition, some geodesic points belonging to the RGAE network (Spanish Antarctic Geodetic network) as fundamental vertices, were used. The tidal data were obtained using pressure sensors installed at the LIVMAR and DECMAR tidal stations, Livingston and Deception islands, respectively, located very close to the Antarctic Bases and Juan Carlos I and Gabriel de Castilla. The first time series were obtained with 798 days of observation in both stations, whose harmonic analysis provided us with 70 tidal constituents, 19 being the most representative with amplitudes greater than 1 cm. With these tidal series we determine the mean sea level, using the LN00 (Deception Island) and BEJC (Livingston island) as a fundamental points. Finally, the precision geoid model, GeoiDEC14, was determined from GPS, gravimetric and leveling measurements. To contrast the results, a comparison of GeoiDEC14 against the most current global models, was made. These are the first results of determining the mean sea level and obtaining a precision geoid model in this Antarctic area. The results obtained improve previous work carried out in the region.