Reference Evapotranspiration Changes: Sensitivities to and Contributions of Meteorological Factors in the Heihe River Basin of Northwestern China (1961-2014)

Abstract

This paper investigates reference evapotranspiration (ET0) changes, sensitivities to and contributions of meteorological factors in the Heihe River Basin (arid and inland region). Results show that annual ET0 over the whole basin has increasing trend (2.01 mm·10 yr-2) and there are significant increasing spatial variations from the upper (753 mm yr-1) to the lower (1553 mm yr-1) regions. Sensitivity analysis indicates that relative humidity is the most sensitive factor for seasonal and annual ET0 change, and the influence is negative. The sensitivity of minimum temperature is the weakest and negative. Contribution analysis shows that the main contributors to ET0 changes are aerodynamic factors rather than radiative factors. This study could be helpful to understand the response of ecoenvironment to the meteorological factors changes in the Heihe River Basin.