Mapping Daily Evapotranspiration Over a Mediterranean Vineyard Watershed

Daily evapotranspiration (ET) was mapped and validated at the regional extent over a vineyard landscape. The mapping was performed using the simplified surface energy balance index (S-SEBI) model, along with an Advanced Spaceborne Thermal Emission and Reflection Radiometer imagery, over two growth cycles. The validation exercise was conducted within a Mediterranean vineyard watershed, over seven sites that differed in canopy, soil, and water conditions. Despite the use of a very simple model over a complex row-structured landscape, the obtained accuracy (0.8 mm/day) was similar to those reported over simpler canopies with full covers, and corresponded to requirements for further applications in agronomy and hydrology, where daily ET can be assimilated into land surface models for calibration and control purposes. An analysis of the validation results suggested that, among the possible factors that could affect S-SEBI performances (spatial variability, vine water status, soil type and color, and row orientation), the first-order influence was row orientation.