Description:
The ETH-GM21 is a new gravimetric geoid model of 2'x2' spatial resolution developed over Ethiopia. This model has been computed using terrestrial and airborne gravity data together with the EIGEN-6C4 GGM and the SRTM3 digital elevation model. The ETH-GM21 model has been determined by using the remove-compute-restore procedure and the least-squares collocation method, obtaining geoid undulations referred to WGS84. With the use of geometric geoid heights obtained from 46 GNSS/levelling data distributed over Ethiopia, the accuracy of the ETH-GM21 gravimetric geoid model has been estimated to ±13 cm. By using the ETH-GQS geoid-to-quasigeoid separation surface over Ethiopia, the ETH-GM21 gravimetric geoid model has been converted into the ETH-QM21 gravimetric quasi-geoid model with the same extension and spatial resolution. The ETH-QM21 model would be beneficial for normal height measurements, also considering the rough topography of Ethiopia.
Model Citations:
E.Y. Belay, W. Godah, M. Szelachowska, R. Tenzer (2021). The Ethiopian gravimetric quasi-geoid: ETH-QM21. V. 1.0. GFZ Data Services.DOI: 10.5880/isg.2021.003
E.Y. Belay, W. Godah, M. Szelachowska, R. Tenzer (2021). The Ethiopian gravimetric geoid: ETH-GM21. V. 1.0. GFZ Data Services. DOI: 10.5880/isg.2021.004
References:
E.Y. Belay, W. Godah, M. Szelachowska, R. Tenzer (2021). ETH-GM21: A new gravimetric geoid model of Ethiopia developed using the least-squares collocation method. Journal of African Earth Sciences, 22, 104313. DOI: 10.1016/j.jafrearsci.2021.104313
E.Y. Belay, W. Godah, M. Szelachowska, R. Tenzer (2022). ETH-GQS: An estimation of geoid-to-quasigeoid separation over Ethiopia. Geodesy and Geodynamics Journal, 13(1), pp. 31-37. DOI: 10.1016/j.geog.2021.09.006
Digital object identifier:
DOI: 10.5880/isg.2021.003 (quasi-geoid in ISG format)
DOI: 10.5880/isg.2021.004
(geoid in ISG format)
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