GRACE Follow-On gravity-field results incorporating the ZARM ACC transplant based on high-precision environment modeling

We have developed a GRACE-D accelerometer product that relies more heavily on modeled acceleration data instead of a transplant. Here we present our approach and a performance evaluation of our data products with different models, processing options and compared to transplant products from other institutes. Comparisons of the artificial acceleration data to the real ACT1B data for GRACE-C show that models related to the atmospheric drag (especially density and drag coefficient) are the limiting factors in the high precision environment modeling approach. Even though it is still possible to generate monthly gravity field solutions with a combination of ACT1B data for GRACE-C and artificial data for GRACE-D that show all prominent hydrological signals, we also implemented a minimalistic transplant where we estimate the atmospheric density from GRACE-C and transplanted it to GRACE-D. We compare our transplant data by incorporation of the GROOPS software to generate monthly gravity field solutions. This enables us to compare the results with other monthly solutions and the ITSG solutions, without getting differences due to the GFR processing tool. We publish the ZARM GRACE-D data product, all modeled non-gravitational accelerations and additional data on a publicly accessible server.