Spectral assessment of recently released CHAMP and GRACE satellite-only earth gravity models

Abstract

In the present study we consider some of the current satellite-only models based on the analysis of CHAMP and GRACE orbital data, computed and released mainly from Geoforschungszentrum Potsdam. In order to obtain a first quantification of their spectral characteristics, a selection of spectral quantities were computed for all of the considered models, namely correlation coefficient per degree, smoothing per degree, and percentage change by degree. Furthermore, typical geodetic measures in computing different geopotential functionals, such as RMS geoid undulation and gravity anomaly difference curves have also been evaluated for the same models, using the combined model EGM96 as reference. The comparisons quantified the level of agreement between different CHAMP-only, GRACE-only and combined models, defining the specific bandwidths where the respective correlations take place.