Abstract

 Different geoid solutions for the Egyptian south-western desert are

carried out in this investigation. The available data for this paper: are 2682

measured gravity values and a set of fine 30″ x 30″ and coarse 3′ x 3′ Digital

Height Models for the area under investigation. The EGM96 geopotential earth

model has been used for removing the effect of the reference filed from the

gravity data. The geoid is computed using various gravity reduction techniques.

They are: the free-air, the Airy-Heiskanen isostatic, the Pratt-Hayford isostatic,

the Vening Meinesz isostatic, the Helmert condensation and the Rudzki inversion

reduction techniques. The reduced gravity anomalies are gridded on a 3′ x 3′

geographical grid using the least-squares interpolation technique with local

covariance functions. These gridded reduced anomalies are used to compute the

different geoid solutions in the frequency domain using the spherical 2D FFT

technique. The relative difference between the different geoid solutions has an

internal accuracy of about 2.5 cm.