A fully remote sensing-based implementation of the two-source energy balance model: an application over Mediterranean crops

Applications of the two-source energy balance (TSEB) scheme require either in-situ meteorological data to characterize the upper boundary conditions or the implementation of complex multi-scale approaches (ALEXI/ DisALEXI). Over remote areas, detailed meteorological forcing (i.e., air temperature and wind speed) are often missing, limiting the quality of the simulated fluxes. To compute surface energy fluxes, the use of wet and dry boundary conditions, commonly referred to as hot and cold pixels, is a widely adopted strategy in thermal-based, single-source surface energy balance models for defining the relationship between satellite land-surface tem perature (LST) and the surface-atmosphere temperature gradient. This contextual scaling approach reduces model sensitivity to biases in LST retrievals, but it has been previously tested within the TSEB modelling framework only in limited capacity. An automatic procedure for retrieving the two boundary temperatures is here proposed, removing the need for ex