Divergent Changes in Terrestrial Water Storage Across Global Arid and Humid Basins

Abstract

Understanding the terrestrial water storage changes (∆S) across global arid and humid river basins is crucial to closing the basin-scale water balance, but still largely unclear. Here, we combine the Gravity Recovery and Climate Experiment, Global Land Data Assimilation System, and WaterGAP Global Hydrology Model products to study ∆S in 197 global river basins with different aridity by using detrended analyses, and find that annual or multiyear mean ∆S is small in most arid basins but relatively larger in humid basins, given the climate change and anthropogenic impacts removed. Through component analysis, we find that the soil moisture changes in drier basins contribute more to ∆S than those in humid basins; and the contribution of groundwater storage changes to (Formula presented.) S is irrelevant to varying moisture conditions. Our results will benefit water balance studies in global river basins (e.g., global evapotranspiration estimation with a water balance approach), and have implications for water cycle studies in the context of global change.