The Roles of Catchment Characteristics in Precipitation Partitioning Within the Budyko Framework

Abstract

AbstractIn the Budyko framework, the landscape parameter (n in the Choudhury‐Yang equation) controls precipitation (P) partitioning to evapotranspiration (ET) and runoff (R). Systematically investigating the underlying influence of catchment characteristics on n is critical for understanding the partitioning of P. Using two runoff datasets with more than 30,000 stations around the world, we found that the variability in n was significantly correlated with a series of catchment characteristics, but varied across climate zones. Hence, several empirical models based on catchment characteristics were developed to estimate n for different climate zones. The developed empirical models applied to Budyko framework explained 92% of the spatial variability in the global mean R and provided more reasonable ET than that from Global Land Evaporation Amsterdam Model (GLEAM) in terms of long‐term water and energy balances. Empirical models were further applied to predict and attribute future R under the high‐end Shared Socioeconomic Pathways (SSP5‐8.5). The changes in P, potential evaporation (PET), and n are projected to alter global R by 61.5%, −24.0%, and 14.5% during 2081–2100. Notably, compare with the historical period, the influence of n was reversed in arid zones under the future scenario, where n leads to a significant decrease in R. The developed empirical models n enhances the applicability and capability of the Budyko framework for both historical and future hydrological assessments over the globe.