Hydro-geodetic approach for predicting river runoff in ungauged basins using gravity and altimetry satellite data

A novel satellite-based approach is proposed for predicting river runoff in ungauged basins using gravity and altimetry data. This hydrogeodetic approach integrates the Gravity Recovery and Climate Experiment (GRACE) observations in the global monthly hydrological model, as an alternative input to in situ runoff. In combination with a water budget equation and by using an efficient innovative multi-objective-optimization algorithm, the problem is solved and validated by three strategies, considering various basins. The results outline a 3-month time shift to consider for the Amazon basin for transiting from storage to runoff, while other basins such as Cheliff, Congo and Daly require runoff bias correction. Basin area and climatic characteristics have demonstrated effects on parameter calibration performance, while the relationship between runoff and space-based river level needs an appropriate mathematical model for each basin. An agreement was found between the predicted runoff and runoff values reported elsewhere, highlighting the effectiveness and feasibility of the proposed approach.