Articles | Volume 19, issue 16
https://doi.org/10.5194/gmd-19-7545-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/gmd-19-7545-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Comprehensive inter-comparison of generative AI models for super-resolution precipitation downscaling across hydroclimatic regimes
Environmental Institute, University of Virginia, Charlottesville, VA, USA
Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
Simon Michael Papalexiou
Institute for Global Water Security, Hamburg University of Technology, Hamburg, Germany
Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic
Hebatallah M. Abdelmoaty
Department of Civil Engineering, Schulich School of Engineering, University of Calgary, Calgary, Canada
Irrigation and Hydraulics Department, Faculty of Engineering, Cairo University, Cairo, Egypt
Tom Hartvigsen
School of Data Science, University of Virginia, Charlottesville, VA, USA
Antonios Mamalakis
CORRESPONDING AUTHOR
Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
School of Data Science, University of Virginia, Charlottesville, VA, USA
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This study compared global satellite and reanalysis precipitation datasets to assess diurnal variability. We found that all datasets capture key diurnal precipitation patterns, with maximum precipitation in the afternoon over land and early morning over the ocean. However, there are differences in the exact timing and amount of precipitation. This suggests that it is better to use a combination of datasets for potential applications rather than relying on a single dataset.
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Ensemble geophysical datasets are crucial for understanding uncertainties and supporting probabilistic estimation/prediction. However, open-access tools for creating these datasets are limited. We have developed the Python-based Geospatial Probabilistic Estimation Package (GPEP). Through several experiments, we demonstrate GPEP's ability to estimate precipitation, temperature, and snow water equivalent. GPEP will be a useful tool to support uncertainty analysis in Earth science applications.
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The study introduces a novel benchmarking method based on the water cycle budget for hydroclimate data fusion. Using this method and multiple state-of-the-art datasets to assess the spatiotemporal patterns of water cycle changes in Czechia, we found that differences in water availability distribution are dominated by evapotranspiration. Furthermore, while the most significant temporal changes in Czechia occur during spring, the median spatial patterns stem from summer changes in the water cycle.
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Short summary
High-resolution precipitation is critical for hydrologic and climate-risk applications, but climate models are too coarse to resolve storm-scale extremes. We compare a deterministic U-NET with two generative models, a Wasserstein Generative Adversarial Network (WGAN) and a diffusion model, for 8× and 16× precipitation downscaling using ERA5-Land. U-NET is stable but smooths extremes, whereas generative models better capture variability and heavy tails while introducing greater uncertainty.
High-resolution precipitation is critical for hydrologic and climate-risk applications, but...