A high-resolution gravimetric geoid in the Strait of Gibraltar

Abstract

A high-resolution gravimetric geoid model in the Strait of Gibraltar is presented. The computations are based in a data set consisting of 104890 free-air gravity anomalies covering the area (33 < phi < 39, -10.5 < lambda < 5.5). the OSU91A geopotential model and a Digital Terrain Model. The remove-restore technique, the Helmert second condensation reduction and the Stokes formula are applied. The computations are made with the spherical 1 D FFT.Discrete spectra of the kernel function are used. In order to avoid circular convolution effects. 100% zero padding has been appended arounded the signal matrix. The result is a 256 x 512 grid referred to the GRS80 system. Comparison with previous geoids in the same area shows an improvement in precision and reliability. The computed geoid is compared with geoid undulations obtained by GPS Levelling, and a precision of 1.0 ppm obtained.