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On a strategy for the use of GOCE gradiometer data for the development of a geopotential model by LSC

Arabelos Dimitrios(1) and Carl C. Tscherning(2)

(1) University of Thessaloniki, Box XX, Thessaloniki, Greece
(2) University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Oe, Denmark

Abstract

For the development of a spherical harmonic expansion of the Earth’s gravity field using point data such as gravity gradient components from GOCE mission, data with a global coverage are needed. For a satisfactory representation of the gravity field in an area using point data of a relevant quantity, the number of the data needed depends on the variance of the gravity field in this area. Therefore, for global coverage, using a proper data distribution it is possible to achieve a good approximation of the gravity field without increasing unnecessarily the number of data, using more data in areas with rugged gravity field and fewer data in areas where the gravity field is smoother. This is essential for methods such as the method of Least Squares Collocation (LSC) where a system of linear equations is to be solved having a number of unknowns equal to the number of input data. The aim of this paper is to suggest a strategy for the collection of point data on real GOCE orbits, leading to optimal LSC determination of spherical harmonic coefficients, with the minimum number of data points. Numerical experiments for the determination of harmonic coefficients were carried out, using noise-free or noisy simulated data with different distributions. The suggested strategy is based on the comparison between computed and true coefficients, the collocation error estimate of the coefficients and the comparison of the original data with data generated by the computed coefficients.

 

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