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Regional Models

South America (GEOID2021/QGEOID2021)


  Authors: A.C.O.C. de Matos, et al.     Created: 2021    Resp: A.C.O.C. de Matos  
                       Status: PUBLIC   Licence: CC BY 4.0
Description:
The South America gravimetric geoid and quasi-geoid models, named GEOID2021 and QGEOID2021 respectively, were computed thanks to a collaboration of several institutions, companies and universities of South America. The models cover the area between 15°N and 60°S in latitude and 100°W and 30°W in longitude, with a grid resolution of 5' x 5'. They are based on 959,404 terrestrial gravimetric points, the XGM2019 global geopotential model up to degree and order 200 and the SRTMv3 digital terrain model. The short wavelengths of the solution were estimated via Fast Fourier Transform (FFT) with the modified Stokes kernel proposed by Vaníček and Kleusberg (1987). On the other hand, long and medium wavelengths were removed and replaced in the framework of a remove-compute-restore procedure. Regions without gravimetric observations were completed using XGM2019 to its full degree. The calculation of the geoid model was performed by the Canadian package SHGEO (Stokes-Helmert Geoid Software). The quasi-geoid model was obtained by the classical geoid/quasi-geoid separation term (Heiskanen and Moritz, 1967). The comparison between the estimated geoid heights and GPS/levelling data at 4464 points in Argentina, Chile, Colombia, Ecuador and Venezuela (2931, 176, 464, 703 and 190 points, respectively) shows differences with an RMS ranging from 34 cm for Argentina to 92 cm for Ecuador. The comparison between height anomalies and GPS/levelling data at 1108 points in Brazil shows differences with an RMS of 41 cm.

Model Citations:
A.C.O.C. de Matos, D. Blitzkow, G.N. Guimarães, V.C. Silva (2021). The South American gravimetric quasi-geoid: QGEOID2021. V. 1.0. GFZ Data Services. DOI: 10.5880/isg.2021.005

A.C.O.C. de Matos, D. Blitzkow, G.N. Guimarães, V.C. Silva (2021). The South American gravimetric geoid: GEOID2021. V. 1.0. GFZ Data Services. DOI: 10.5880/isg.2021.006

Reference:
A.C.O.C. de Matos, D. Blitzkow, G.N. Guimarães, V.C. Silva (2021). Geoid and quasi-geoid models for South America
. Presented at SIRGAS Symposium 2021, 29 November - 1 December 2021, online.

Digital object identifier:
DOI: 10.5880/isg.2021.005 (quasi-geoid in ISG format)
DOI: 10.5880/isg.2021.006 (geoid in ISG format)

South America