Achieving water budget closure through physical hydrological processes modelling: insights from a large-sample study.

Modern hydrology is embracing a data-intensive new era, information from diverse sources is currently providing support for hydrological inferences at broader scales. This results in a plethora of data reliability-related challenges that remain unsolved. The water budget non-closure is a widely reported phenomenon in hydrological and atmospheric systems. Many existing methods aim to enforce water budget closure constraints through data fusion and bias correction approaches, often neglecting the physical interconnections between water budget components. To solve this problem, this study proposes a Multisource Datasets Correction Framework grounded in Physical Hydrological Processes Modelling to enhance water budget closure, called PHPM-MDCF. The concept of decomposing the total water budget residuals into inconsistency and omission residuals is embedded in this framework to account for different residual sources. We examined the efficiency of PHPM-MDCF and the residuals distribution across 475 CONUS basins selected by hydrological simulation reliability. The results indicate that the inconsistency residuals dominate the total water budget residuals, exhibiting highly consistent spatiotemporal patterns. This portion of residuals can be significantly reduced through PHPM-MDCF correction and achieved satisfactory efficiency. The total water budget residuals have decreased by 49 % on average across all basins, with reductions exceeding 80 % in certain basins. The credibility of the correction framework was further verified through several noise experiments. In the end, we explored the potential factors influencing the distribution of residuals and found notable scale effects where residuals decrease with increasing basin area. This emphasizes the importance of carefully evaluating the water balance assumption when employing multisource datasets for hydrological inference in small basins. [ABSTRACT FROM AUTHOR]