Terrestrial Evaporation and Moisture Drainage in a Warmer Climate
Daniel J. Short Gianotti, Ruzbeh Akbar, Andrew F. Feldman, Guido D. Salvucci, Dara Entekhabi
Abstract
Abstract To determine hydrologic changes in a warmer climate, we impose precipitation and potential evaporation ( E o ) perturbations on hydrologic response functions constructed from precipitation and satellite soil moisture observations across the United States. Despite nonlinearities in the evaporation ( E ) and drainage ( D ) responses and opposing‐sign perturbations, changes in individual fluxes are superposable. Empirical frameworks (Budyko) can misrepresent changes in E / D partitioning by neglecting shifts/trends in hydrologic regime and subseasonal precipitation dynamics. E / D both increase to balance mean precipitation ( ) increases, and increased E o reduces soil moisture. E and D are generally more elastic to changes in than E o . The results suggest that (1) the impacts of regional hydrologic perturbations may allow for simple superposition/scaling, (2) changes in timing/intensity of precipitation may have substantial impacts on mean moisture states and fluxes, and (3) changes to the distribution of surface moisture states are likely more relevant for E / D partitioning than common aridity indices.