Derivation of an exponential complementary function with physical constraints for land surface evaporation estimation

Abstract

The complementary principle provides a simple method for estimating land surface evaporation using standard meteorological observations and has received increasing attention in recent years. In this study, we propose an exponential generalized complementary function that satisfies the physical boundary conditions and constraints proposed by Brutsaert (2015). With one adjustable parameter, the new exponential function is validated using observations from 21 FLUXNET stations, and the results show that the exponential function can efficiently simulate actual daily evaporation. A comparison between the exponential function and the polynomial function proposed in previous studies suggests that the exponential function can improve the accuracy, reasonableness and flexibility of land surface evaporation estimation. Overall, the exponential function provides a new method for estimating land surface evaporation and may enhance our understanding of the complementary principle.