Un modelo de mareas para el Observatorio Argentino-Alemán de Geodesia (AGGO) utilizando observaciones del gravímetro superconductor SG038

Abstract

The Argentinean-German Geodetic Observatory (AGGO) is a fundamental geodetic observatory located close to the city of La Plata, Argentina. All relevant space geodetic techniques are established at AGGO: GNSS, VLBI and SLR. A Gravity Lab is also installed, where the superconducting gravimeter (SG) SG038 has been continuously measuring gravity variations since December 2015. Moreover, the absolute gravimeter FG5-227 has provided a gravity reference value for the Observatory and Latin America since January 2018. Through the analysis of three years of superconducting gravity data, an Earth tidal model is presented. The SGs are capable to measure gravity variations in a wide range of amplitudes and frequencies, from Earth tides to hydrological effects. In order to analyse different effects in the SG observations, a careful pre-processing of the signal has to be done before. To do so, the preliminary residuals were obtained by subtracting the principal constituents of the signal. Spikes caused by earthquakes were eliminated and a few gaps were filled. The residuals were then filtered to obtain a smooth and continuous signal. Afterwards, Earth tides and ocean tide loading signals that were previously subtracted, were restored to the corrected residuals. The tidal analysis was performed with the last version of the ETERNA ETA34-X software, including independent estimates of degree 3 of the potential of some tidal constituents. After the tidal analysis of three years of SG observations, parameters of 55 tidal constituents were obtained. Moreover, in order to separate the effects of Earth tides and ocean tide loading, different ocean tide models were compared.