The research project ATMO-CHAMP/GRACE was funded within the GEOTECHNOLOGIEN programme of BMBF (2009-2011).

During the 2nd period of the GEOTECHNOLOGIEN key research area "Observation of System Earth from Space" (research project NRT-RO) GPS RO measurements from CHAMP and GRACE were provided in Near-Real Time for the DWD and international weather services. The operational data use by the weather centers is a milestone for the acceptance of the GPS RO technique by the atmospheric scientists on the way to an established remote sensing method. In focus of this project is the long-term data set from CHAMP and GRACE whose unique temporal range enabled already initial climatological investigations. Several studies, comparing RO analysis results of different processing centers, show in general excellent agreement of results from different centers, but also indicate slight differences which need to be clarified especially regarding climatological applications. Major goal of this project is the analysis of these differences in more detail and based on these investigations the generation of a consistent and high quality long-term data set from CHAMP and GRACE. A further major objective is the demonstration of various applications for the long-term data set. These applications include long-term analysis of global temperature/refractivity and atmospheric water vapor trends in the upper atmosphere, investigations related to global characteristics of the tropopause structure and gravity wave distribution. This work will be completed by the generation and interpretation of climatologies of disturbances in the lower ionospheric E-region, which can be derived from the GPS RO data. These data provide important information on vertical atmospheric coupling processes and their long-term variation.