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Regional Models

Africa


  Authors: H.H. Fashir, M.A. Kadir     Created: 1997    Resp: H.H. Fashir 
      Status: ON-DEMAND   

Description:
Regional geoid computed for the whole Africa, ranging from 350 S to 400 N in Latitude and 200 W to 500 E in Longitude. The EGM96 geopotential model truncated to degree and order 70 was combined with surface gravity data and modified Stokes's Kernel to generate the geoid file. The surface data consists of 10 x 10, 30' x 30' mean gravity anomalies and 30'x 30' topographic information (coming from NIMA and OSU).
Comparison of the gravimetric geoid with the Doppler/levelling derived geoidal heights of 92 stations all over Africa shows that the absolute agreement with respect to the Doppler/levelling datum is generally better than 1.85m RMS.   Other global models, such as OSU91A and EGM96 complete to degree and order 360 were also included in the comparison, showing that the new gravimetric geoid achieves the best agreement with the Doppler/levelling data.
Data are in meters, stored in an ASCII file, in grd format, parallelwise from N to S and from W to E.

References:
H.H. Fashir, M.A. Kadir (1998). African regional gravimetric geoid 1997: Stokesian approach. IGeS Bulletin, 8, pp. 65-84.

Africa