Integrating super resolution mapping and SEBS modeling for evapotranspiration mapping at the field scale

This study addresses the use of super resolution mapping (SRM) for precision agriculture. SRM was applied to a high resolution GeoEye image of a vineyard in Iran with the aim to determine the actual evapotranspiration (AET) and potential evapotranspiration (PET). The Surface Energy Balance System applied for that purpose requires the use of a thermal band, provided by a Landsat TM image of a 30 m resolution. Image fusion downscaled that information towards the 0.5 by 0.5 m2 scale level. The geometry was validated with an UltraCam aerial photo. Grape trees in the vineyard were planted in rows and three levels were distinguished: the field, rows and individual trees. AET values thus obtained ranged within rows from 5.32 (SD = 0.26) to 5.39 (SD = 0.24), whereas values for individual plants ranged from 5.29 (SD = 0.22) through 5.33 (SD = 0.39) to 5.36 (SD = 0.23). The study showed that AET values were obtained close to 5.71 mm day−1 derived by standard calculations at the field scale, but spatial variability was clearly present. The study concluded that modern satellite derived information in combination with recently developed image analysis methods is able to provide reliable AET values at the row level, but not yet for every individual grape tree