Data Coverage Improvement for Geoid Computation in South America
The Sub-Commission for the Geoid in South America (SCGSA) is in the process of improving the geoid model in South America. The geoid model is mainly derived from the gravity data coverage resulting from the South American Gravity Project (SAGP, 1988–1991) which has been significantly improved in Brazil, Argentina and Chile during the period of 1991–1997, and from GPS observations along lines of geometric levelling in Brazil, Argentina and Venezuela. New efforts are also being made in Colombia to reorganize their gravity data. In addition, a major digitising programme has resulted in a new digital terrain model of South America on a 3’ grid that significantly improves ETOPO5. The SIRGAS (Geocentric Reference System for South America) project has given a new emphasis to these initiatives. A new geoid model for South America with a resolution of 20’ is presented and comparisons of 460 GPS/Doppler heights are made, with both the new geoid and the OSU91A geopotential model.
KeywordsGravity Anomaly Gravity Data Digital Terrain Model Geoidal Height Geopotential Model
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