Partitioning of Precipitation Into Terrestrial Water Balance Components Under a Drying Climate

To accurately project future water availability under a drying climate, it is important to understand how precipitation partitioned into other terrestrial balance components, such as fluxes (evaporation, transpiration, runoff) and changes in storage (soil moisture, groundwater). Many studies have reported unexpected large runoff reductions during drought, particularly for multi-year events, some report persistent change partitioning even after the meteorological drought has ended. This study focused on understanding actual evapotranspiration (AET) subsurface (ΔS) respond climate variability change, examining Australia's Millennium Drought (MD, 1997–2009). The initially conducted catchment-scale analysis investigate interactions between ΔS AET. Then was extended regional scale using interpolated rainfall discharge with remotely sensed Lastly, we evaluated conceptual rainfall-runoff model performance of two commonly used models against these estimates. evaluation water-balance-derived Gravity Recovery Climate Experiment (GRACE) estimates shows significant multiyear decline; however, different rates. In contrast, AET rates (annualized) remained approximately constant before MD, contrasting reports enhancement elsewhere. Overall, given constant, drought-induced were streamflow. employed failed realistically represent suggesting need improved conceptualization processes. provides useful implications explaining hydrological if similar behavior observed climate.