Estimation of air temperature and reference evapotranspiration using MODIS land surface temperature over Greece

ABSTRACTModerate Resolution Imaging Spectroradiometer (MODIS), land surface temperature data, during daytime (LSTday) or night-time (LSTnight), were employed for predicting maximum (Tmax) or minimum (Tmin) air temperature measured at ground stations, respectively, in order to be used as alternative inputs in minimum data-based reference evapotranspiration (ET) models in 28 stations in Greece during the growing season (May–October). The deviations between daily LSTnight and Tmin were found to be small, but they were greater between LSTday and Tmax. Furthermore, the temperature vegetation index (TVX) method was employed for achieving more accurate Tmax values from LSTday, after determining the normalized difference vegetation index of a full canopy (NDVImax). The TVX method was validated on ‘temporal’ basis, but when the method was tested spatially, the improvement on the Tmax estimates from LSTday was not encouraging, for being used operationally over Greece. Thus, LSTday or LSTnight MODIS data were used a...