The progress of the geoid model for South America under GRACE and EGM2008

Abstract

The efforts to compute the geoid model for South America, limited by 15° N and 57° S in latitude and 30° W and 95° W in longitude, are presented. The terrestrial gravity data for the continent have been updated with the most recent measurements in Argentina, Brazil, Chile, Ecuador and Paraguay. An attention was also addressed to DTM, on the basis of SRTM (Shuttle Radar Topography Mission). The complete Bouguer gravity anomaly; the direct, secondary and primary indirect topographic effects; and direct and primary indirect atmospheric effects have been derived through the Canadian package SHGEO (Stokes-Helmert Geoid software). The short wavelength component was estimated via FFT with Featherstone, Evans and Olliver (1998) modified kernel. The geopotential model EGM2008 represents an important contribution to the long and medium wavelength component knowledge of the gravitational field and it has been used as a reference field restricted to degree and order 150. The model has been validated over 1,411 GPS observations on Bench Marks of the spirit leveling network, where the geoidal height was derived from the association of the geodetic and the orthometric heights. © Springer-Verlag Berlin Heidelberg 2012.