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Constraints on Shallow Low-Viscosity Earth Layers from Future GOCE Data

Hugo Schotman(1,2), Bert Vermeersen(1) and Pieter Visser(1)

(1) Delft University of Technology, Kluyverweg 1, 2629 HS Delft, Netherlands
(2) SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, Netherlands

Abstract

In previous papers (Schotman and Vermeersen, Earth Planet. Sci. Lett. 236 (2005), Schotman, Vermeersen and Visser, Proc. IAG (2006, in press)) we have shown that geoid heights due to shallow, laterally homogeneous low-viscosity earth layers are above the performance of GOCE, and that GOCE is especially sensitive to the properties of crustal low-viscosity layers and uncertainties in the ice-load history. Here we will try to recover properties of crustal low-viscosity layers from synthetic GOCE data, in the presence of error sources. We will group these error sources in model errors and noise.

Model errors include errors in the background models (e.g. the GIA earth and ice model combination), unmodelled medium- to short-wavelength (harmonic degree above 20) solid-earth features related to subduction, passive margins and topography, time-dependent mass variations in the oceans and atmosphere, and errors in the recovery of the gravity field from simulated gravity gradients. Noise consists of random mass inhomogeneities in the shallow earth and realistic gradiometer measurement noise.

We will focus on a region where other solid-earth aspects contribute to the static gravity field, and use a combined spectral-spatial domain approach to separate the different contributions. We will give an estimate of how well homogeneous crustal low-viscosity layers can be constrained by GOCE data and shortly expatiate on the validity of our conclusions for laterally heterogeneous low-viscosity layers.

 

Workshop presentation

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