Topographic Reductions in Gravity and Geoid Modeling

Abstract

This chapter focuses on a review of the conventional methods widely used for the computation of the effects of topography and bathymetry in geoid and quasi-geoid modeling. Terrain and bathymetry models of high-resolution and accuracy are used in order to provide the high-frequency content of the gravity field spectrum through the available mass reduction methods (e.g., terrain corrections, simple and refined Bouguer effects, residual terrain model, isostatic reduction schemes). Several other reduction schemes (e.g., the Rudzki and Poincaré and Prey reductions), which are briefly discussed herein, can be possible alternatives of computation of mass effects in gravity field modeling, although they are not commonly used in geodetic applications. The high-frequency contribution of the topographic and bathymetric effects to gravity-field related quantities (e.g., gravity anomalies, gravity disturbances, geoid undulations, deflections of the vertical, gravity gradients) is primarily due to the strong correlation of the short-wavelength gravity features with topography and bathymetry.