Annual water deficit in response to climate variabilities across the globe

Abstract

Severe water deficits due to abnormal climatic conditions can be observed in hydrology and agriculture and can be assessed by various characteristics of the water system that showdifferent responses to climate variability. This paper comprehensively investigates the sensitivities of hydrological (i.e. streamflow and water storage) and agricultural (i.e. plant water availability) water deficits to climate variability at a global scale from a hydrological cycle perspective. The sensitivities of 77 large basins across the globe are quantified by both multiple linear regression (MLR) and the Budyko framework based on a newly released terrestrial water cycle dataset. We find that streamflow and water storage deficits are generally more sensitive to rainfall variation, while plant water availability is more responsive to variations of potential evapotranspiration. The climate sensitivities of the water deficit indices are shown to vary with the wetness index and are shaped by catchment surface properties like water storage capacity. The sensitivities of streamflow deficits to rainfall are higher in wetter regions, while the sensitivities of plant water availability to potential evapotranspiration are higher in drier regions. The findings about the divergent responses in water deficit indices can be conducive to developing region-dependent water resource management strategies to alleviate water deficits under a changing environment.