The influence of different crust models on the gravity field of the Earth

By describing the geoid in relation to a reference ellipsoid as a particular equipotential surface of .the Earth’ s gravity field, we end up with the well-known problem that the density distribution of the Earth is not exactly known. The Earth’ s crust, in particular, is of major interest because it produces the medium and short wavelength constituents in the variation of the geoid. To model the crust, we can use the three famous isostatic models of Pratt-Hayford, Airy-Heiskanen and Vening Meinesz, or, additional information about the density distribution and the depth of the Mohorovicic discontinuity. The influence of different crust models on the gravity field of the Earth, especia1ly on the geoid, can reach several centimeters. This will be illustrated with the isostatic models of Pratt-Hayford and Airy-Heiskanen for the area of Baden- Wlirttemberg in Germany.