BMBF Geotechnologien REAL-GOCE WP 140

01.Jun.2009 - 31.May.2012

Akbar Shabanloui
Judith Schall
Annette Eicker

The Astronomical, Physical and Mathematical Geodesy Group of the Institute of Geodesy and Geoinformation, University of Bonn, ( has been involved in the de-velopment of models and techniques to determine the gravity field from observations of the new grav-ity satellites for years. The Gravity Recovery Object-Oriented Programming System (GROOPS) has been developed for this task. It is tailored to the processing of the in-situ observables of the new gen-eration of gravity satellite missions such as CHAMP, GRACE and GOCE and shall be extended now to the processing of real GOCE-level-1b-data. The real-data-processing modules are already imple-mented for the observations of CHAMP and GRACE, but not yet for the processing of the gravity gra-dients measured by the GOCE gradiometer as well as for the analysis of the precise orbits of GOCE (POD-solution). The respective modules for the GOCE data processing are designed for processing simplified simulated data sets and shall be adapted in this project to the real case. The envisaged re-sults consist of GOCE gravity field models: GOCE-only gravity field models, represented by directly determined spherical harmonics on the one hand and regionally refined and subsequently merged to global gravity field models on the other hand. Further results are combined consistent satellite-only gravity field models, e.g., based on combinations of GOCE-GRADIENT+GOCE-POD+GRACE data. Finally, it is planned, to derive combined gravity field models which consist on properly weighted GOCE-only gravity field models, GRACE-only gravity field models and terrestrial data (altimetry da-ta, absolute and relative gravity measurements as well as gravity field information from digital eleva-tion models). The regional refinements can be used also for the cal/val as well as for the combination segment of this project. For selected oceanic regions with rough gravity field structures and moderate temporal sea surface variations regionally refined gravity gradients at satellite altitude shall be com-pared to high-resolution altimetric gravity field analysis results (WP 110).