Background
To observe mass distribution and mass transport in System Earth on a global scale, with homogeneous accuracy and over long time periods, dedicated gravity satellite missions are required. These missions were and are developed and operated in strong collaboration with German Industry, NASA, ESA, DLR and the German Satellite Operations Center (GSOC). Analysis of the mission science data is performed using our own developed Earth Parameter and Orbit System (EPOS) software using up to date international standards.
Both missions are equipped with highly sensitive instruments, such as a high-precision inter-satellite link for measuring smallest changes in distance between the twin satellites or accelerometers to observe non-gravitational forces. GFZ has played and continues to play a leading role in the evaluation and operation of these modern satellite missions. We were and are part of the joint German/US Science Data System (SDS) for both missions. There we use the Level-1B instrument data to calculate monthly Level-2 gravity field models. In addition, more user-friendly Level-3 products are generated from these models by converting the Level-2 spherical harmonic coefficients into gridded functionals of the Earth's gravity potential (such as change in the equivalent water column). All data are offered free of charge to users at the GFZ via the Information System and Data Center (ISDC). Level-3 data can also be visualized in the Gravity Information System (GravIS).
GFZ operates a satellite receiving station in Ny-Ålesund on Spitsbergen to continuously monitor the health of the satellites and instruments and to download nearly every satellite revolution the Level-0 raw data from the satellites to the ground. The routine operation of the satellites at GSOC is supervised by the GFZ Deputy Operations Mission Manager.
Detailed information on data analysis and mission can be found on the GRACE, GRACE-FO and GRACE-C project pages.
Scientific key questions
- How can the accuracy of the monthly gravity field models be further improved?
- What climate-related changes in the Earth system can be derived from the time series since 2002?
- How can the operation of the GRACE-FO satellites and their instruments be further optimized so that additional data can be obtained for as many years as possible?
Related projects
