Future Reference Evapotranspiration Projection and the Potential Uncertainties from Various Approaches with the Combination of Different Estimating Formulations and Input Data Reliabilities

Abstract:

Reliable estimation of future reference evapotranspiration forms the basis of assessing hydrological response and water resources to changing climate condition. Different estimating formulations and different input data reliabilities existing in practice determine there may be potential uncertainty in projection of future reference evapotranspiration change. Should we use more reliable physically-based methods (e.g., Penman–Monteith) but with insufficient or uncertain data quality, or should we employ more empirical methods (e.g., temperature-based methods) with more reliable input data. Three different approaches were used to explore the method dependence in projection of the future reference evapotranspiration. Uncertainties lied in estimating how much the reference evapotranspiration changed. Yet meanwhile, in a certain degree, coincident results on the overall pattern of further deduced aridity index and water surplus changes based on reference evapotranspiration by these three approaches place an important basis to develop robust and equitable water management adaptation to climate change.