The first high-resolution gravimetric geoid for Argentina: GAR

Abstract

This paper describes the new geoid model for Argentina. As only very few geoid solutions are published for South America, any new geoid model could be considered very important. As expected the obtained geoid solution have better accuracy and reliability, than the global EIGEN-GL04C model, which was derived recently with the most advanced techniques and the best database available up to 2006. The computation method was the Stokes integral in convolution form, which is proved as an efficient tool to reach the expected objective. The terrain corrections have been computed from a digital terrain model based on the SRTM (Shuttler Radar Topography Mission) 90M database. These corrections were used to obtain the residual anomalies from the gridded gravity anomalies. The indirect effect has been also taken into account. The new geoid model is obtained on a regular 1.5′ × 1.5′ grid in the GRS80 reference system, covering Argentina and the surrounding area, from −56° to −21° of latitude and from −75° to −53° of longitude. This gravimetric geoid and the EIGEN-GL04C model are compared to geoid undulations derived at 393 GPS/levelling points, located at the study area. As it is expected, the new geoid shows a better fit at the 393 validation points than the global geoid model. The new gravimetric geoid solution could be very important for engineering purposes to provide an improved reference surface may be used in connection with GPS measurements and altimetric observations, as well as for geophysical purposes.