GRACE/GRACE-FO RL07 Reprocessing at CSR: Algorithmic Updates, Performance Improvements and Results

More than 24 years of time-variable gravity observations from the GRACE and GRACE-FO missions have greatly advanced our quantitative understanding of mass redistribution within the Earth system, including terrestrial hydrology, ocean mass variability, cryospheric change, solid Earth processes, and climate-driven signals. The GRACE and GRACE-FO datasets are currently undergoing RL07 reprocessing at the Center for Space Research (CSR) to further reduce noise and systematic errors, improve solution consistency, and establish a uniform long-term archival record that supports multi-decadal mass change analyses across the GRACE and GRACE Follow-On missions.

The RL07 reprocessing includes a complete reanalysis of Level-1B observations, updates to reference frames and background geophysical models, and a series of improvements to orbit determination and gravity field recovery. Key enhancements include improved treatment of GNSS and K-band ranging observations, refined instrument error calibration, and updated processing and stochastic modeling strategies. In parallel, a new generation of CSR mascon solutions is produced using methodologies fully consistent with the RL07 framework. This paper describes the major upgrades implemented in the CSR RL07 reprocessing of GRACE and GRACE-FO data and assesses their impact on solution stability, noise characteristics, and the fidelity of time-variable gravity signals. Relative to CSR RL06, the RL07 solutions exhibit more than a 35% reduction in noise, quantified as root-mean-square (RMS) variability over the oceans, which translates directly into a substantial improvement in the realized spatial resolution of GRACE and GRACE-FO mass change estimates.