ReSET-Raster: Surface Energy Balance Model for Calculating Evapotranspiration Using a Raster Approach

Abstract

Surface energy balance models developed for mapping evapotranspiration at high resolution use weather station data. Previous models such as SEBAL or METRIC use wind and reference evapotranspiration from a single weather station. A third model (ReSET) uses wind run from multiple weather stations but uses a single weather station for the internal calibration. Because these models solve the energy balance equation for areas that usually have significant spatial variability, it is more appropriate to have all inputs and calculations in a raster format. This paper presents a full rasterized model, which uses all inputs and performs all calculations in a raster format (ReSET-Raster). The ReSET-Raster model provides the flexibility to use several weather stations as data sources to generate interpolated weather parameters in a raster format. It explicitly takes into account the spatial variation of weather parameters between weather stations, which can be significant. This paper presents examples showing that evapotranspiration calculated with the raster approach can vary as much as 17% compared with evapotranspiration calculated with point values.