Recent Advances in the Two Source Energy Balance Model to Calculate E, T, and ET for Row Crops.

Calculation of evaporation (E), transpiration (T), and evapotranspiration (ET) are fundamental to assess strategies and tactics that might improve crop water productivity in both irrigated and dryland production systems. One approach to calculate E, T, and ET is by a two-source energy balance model (TSEB), which calculates the energy budget of the soil and canopy separately. A remote sensing-based TSEB has been developed that only requires a single measurement of directional surface brightness temperature, commonly available meteorological variables, and measurements or estimates of crop phenology. Recent advances in the TSEB have addressed several aspects that relate to the nonrandom spatial distribution of row crop vegetation, the unique view geometries of ground-based remote sensing platforms, and the wide range of meteorological conditions that are typical of semiarid, advective climates. These advances were applied to the TSEB and tested against measurements of E, T, and ET using microlysimeters, sap flow gauges, and large weighing lysimeters, respectively. This presentation will review these advances and discuss needs for future research.