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Regional Models

Sudan (KTH-SDG08)

  Authors: A. Abdalla, D. Fairhead     Created: 2008    Resp: A. Abdalla 
      Status: ON-DEMAND   
The Sudanese gravimetric geoid model (KTH-SDG08) is computed by applying the method developed at the KTH, which is based on least-squares modification of Stokes formula. Two sets of regional gravity data are used: the first one is provided by the GETECH, the points of this set cover discretely some parts of Sudan while the rest of the country is still not covered, the second one is provided by BGI and contains a few points scattered over the neighbouring countries. The long-wavelength contribution is taken from two geopotential models: EIGEN-GRACE02S satellite-only model is employed in the modified Stokes formula, whereas the EIGEN-GL04C combined model is used to enrich the local gravity coverage over the areas with missing data. SRTM is used to compute topography effects on the geoid. The KTH-SDG08 model is computed on a 5 x 5 arc-min geographical grid over the computation area bounded by the parallels of 4 and 23 arc-deg northern latitude, and the meridians of 22 and 38 arc-deg of eastern longitude. The geoid heights are with respect to the GRS80 reference ellipsoid. The gravimetric geoid is validated using GPS-levelling information at 19 points distributed over the whole country, showing a standard deviation of about 0.3 m.

A. Abdalla (2009). Determination of a gravimetric geoid model of Sudan using the KTH method. Master's of Science Thesis. Royal Institute of Technology (KTH), Stockholm, Sweden.
A. Abdalla, D. Fairhead (2011). A new gravimetric geoid model for Sudan using the KTH method. Journal of African Earth Sciences, 60(4), pp. 213-221. DOI: 10.1016/j.jafrearsci.2011.02.012

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