Remote sensing of crop water requirements in orange orchards using high spatial resolution sensors

With the aim to derive crop water requirements (ETp) for an irrigated area covered by orange orchard in Sicily, QuickBird and ASTER TERRA high resolution satellites data were used and compared with reference to their different spatialand spectral resolution. Satellites data allowed to improve the monitoring of canopy development in the irrigated area byidentifying biophysical vegetation variable (LAI, albedo, vegetation indicators, etc…); this information was successivelyused for the evaluation of maximum crop water needs by means of the well known Penman-Monteith equation.The paper results evidence the importance of very-high resolution sensors such as QuickBird in areas characterised bystrong spatial heterogeneity. The algorithms applied to estimate the canopy parameters and the crop water requirementswere applied by considering different levels of radiometric calibration of the satellite data, which produced markeddifferences in the final results.