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Comparison of the modelling of topographic and isostatic masses in the space and the frequency domain for use in satellite gravity gradiometry

Franziska Wild(1) and Bernhard Heck(1)

(1) University of Karlsruhe, Englerstr. 7, 76128 Karlsruhe, Germany


In terrestrial and airborne gravity field determination the formulae for the gravitational potential and its first order derivatives have been evaluated, while 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 within the remove-restore concept is important to produce a smooth gravity field suitable for downward continuation. Another application of topographic and isostatic reductions consists in the external calibration of the GOCE gravity gradiometer. In this presentation, the modelling in the space domain is opposed to the modelling in the frequency domain. In the space domain the gravitational effects of volumetric mass elements can be presented by prisms, point masses, mass layers and tesseroids. The volume integrals are analytically solvable for all mentioned mass elements, except the tesseroid. Approximate solutions of the elliptic integrals related to the tesseroid can be produced by semi-analytical or purely numerical methods. Based on different isostatic models the topographic-isostatic effects are calculated for a GOCE-like satellite orbit, and the computation methods in the space and frequency domain are compared.


Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry