Groundwater is a critical resource in Iran’s border regions, where surface-water scarcity has intensified reliance on subsurface reserves, leading to overextraction and rapid depletion. Sustainable management in these arid areas demands high-resolution, continuous data, yet field-based monitoring remains limited by cost and logistical challenges. Satellite remote sensing, particularly the GRACE mission, provides essential large-scale terrestrial water storage anomaly (TWSA) estimates but suffers from coarse spatial resolution that constrains local applications. This study introduces a machine learning-based framework to downscale GRACE-derived terrestrial water storage anomaly and simulate groundwater level change at a finer resolution of 0.25° (~ 25 km). A random forest model was applied to refine GRACE data from 1 to 0.25° resolution using predictors such as precipitation, evapotranspiration, land surface temperature, and vegetation indices. The downscaled dataset, combined with ancillary hydrological variables, supported the development of a second random forest model for monthly groundwater level change prediction, validated against in situ piezometric data. Results indicated strong model performance, with R 2 values of 0.90 and 0.74 for training and testing phases, respectively, confirming the framework’s ability to capture groundwater fluctuations across diverse aquifers. The study highlights the potential of integrating downscaled satellite observations with machine learning to enhance groundwater assessment and support data-driven management in water-stressed environments.
Khalaj et al. (Thu,) studied this question.