Smoothing the Gradiometric Observations Using Different Topographic–Isostatic Models: A Regional Case Study

Abstract

In terrestrial and airborne gravity field determination the formulae for the gravitational potential and its first order derivatives have been used, while the second order derivatives are related to the analysis of upcoming satellite gravity gradiometry missions of GOCE type. Especially there, the reduction of topographic and isostatic effects is important to produce a smooth gravity field suitable for downward continuation. In this paper various isostatic models, namely the models of Airy–Heiskanen (A–H) and Pratt–Hayford (P–H), the combination of the Airy–Heiskanen model (land area) and the Pratt–Hayford model (ocean area), the first (H1) condensation model of Helmert as well as a crust density model are analyzed for a GOCE-like satellite orbit in two selected regions: Japan and central part of Europe. The different topographic–isostatic effects are compared with respect to the degree of smoothing of the measured satellite gradiometric data. The results of this paper can serve as a base for further investigations of the suitability of particular reduction models for downward continuation.