Functional relationships reveal differences in the water cycle representation of global water models

Gnann, Sebastian; Reinecke, Robert; Stein, Lina; Wada, Yoshihide; Thiery, Wim; Satoh, Yusuke; Pokhrel, Yadu; Ostberg, Sebastian; Koutroulis, Aristeidis; Hanasaki, Naota; Grillakis, Manolis; Gosling, Simon N.; Burek, Peter; Bierkens, Marc F. P.; Wagener, Thorsten

Abstract

AbstractGlobal water models are increasingly used to understand past, present and future water cycles, but disagreements between simulated variables make model-based inferences uncertain. Although there is empirical evidence of different large-scale relationships in hydrology, these relationships are rarely considered in model evaluation. Here we evaluate global water models using functional relationships that capture the spatial co-variability of forcing variables (precipitation, net radiation) and key response variables (actual evapotranspiration, groundwater recharge, total runoff). Results show strong disagreement in both shape and strength of model-based functional relationships, especially for groundwater recharge. Empirical and theory-derived functional relationships show varying agreements with models, indicating that our process understanding is particularly uncertain for energy balance processes, groundwater recharge processes and in dry and/or cold regions. Functional relationships offer great potential for model evaluation and an opportunity for fundamental advances in global hydrology and Earth system research in general.

Citation

Gnann, S., Reinecke, R., Stein, L., Wada, Y., Thiery, W., Satoh, Y., Pokhrel, Y., Ostberg, S., Koutroulis, A., Hanasaki, N., Grillakis, M., Gosling, S. N., Burek, P., Bierkens, M. F. P., & Wagener, T. (2023). Functional relationships reveal differences in the water cycle representation of global water models. Nature Water, 1, 1079-1090. https://doi.org/10.1038/s44221-023-00160-y

• Journal Article Type: Article
• Acceptance Date: Oct 13, 2023
• Online Publication Date: Nov 27, 2023
• Publication Date: 2023-12
• Deposit Date: Oct 27, 2023
• Publicly Available Date: May 28, 2024
• Journal: Nature Water
• Electronic ISSN: 2731-6084
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 1
• Pages: 1079-1090
• DOI: https://doi.org/10.1038/s44221-023-00160-y
• Public URL: https://nottingham-repository.worktribe.com/output/26535809
• Publisher URL: https://www.nature.com/articles/s44221-023-00160-y