A TSAR model for daily evapotranspiration at broad spatial scales: A case study in Northern China

It is technically difficult to estimate the evapotranspiration over a large area due to variation of the effect of canopy microclimate on vegetation and soil processes. In this study, an approach is developed to model daily evapotranspiration from the canopy layer and soil surface of large areas by combining remotely sensed data and ground-based meteorological variables. Combined with vegetation fraction data, a two-layer soil-vegetation atmosphere resistance (TSAR) model for the estimation of regional daily evapotranspiration is derived. A case study in Northern China shows that this model requires less ground information and is much simpler computationally than previous methods, while maintaining reasonably accurate results. The variation and characteristics of evapotranspiration over Northern China are also discussed.