Assimilation of potential field data into hydrological models

Time-variable geopotential data from the Gravity Recovery And Climate Experiment (GRACE) mission, when used in conjunction with radar altimetry data, offer an opportunity to observe (sub-)surface water mass changes from space. In this project, we aim to build a data assimilation framework for combining these data with land surface/groundwater models such as Parflow-CLM. GRACE derived vertically integrated total water storage (TWS) changes and waveform-retracked radar altimetry data over lakes, rivers, and wetland shall be integrated, using ensemble methods such as the EnKF. In addition, simulations will be run for future missions such as GRACE-Follow-On, which probably resolve TWS at scales smaller than 100 km. Due to the huge amount of observations and model parameters, HPC is absolutely required and efficient algorithms have to be developed.