Merging micro-meteorology and Landsat imagery to monitor daily evapotranspiration at a regional scale

The objective of this work is to show the operational applicability of a recently proposed model (Sánchez et al., 2008) together with satellite images to monitor surface energy fluxes at a regional scale. In particular, we will focus on the retrieval of daily evapotranspiration because of the particular significance of this flux in the generation of precipitation or in agricultural water resource management. A detailed methodology to apply the Simplified Two- Source Energy Balance method to Landsat imagery is presented. The different surface cropland features are characterized from the CORINE Land Cover maps, and the required meteorological variables are obtained by interpolating the data of a network of agro-meteorological stations distributed within the region of interest. Finally, we show the application of the methodology to three different Landsat images covering the whole Basilicata region (Southern Italy). Maps of the different fluxes including the daily evapotranspiration are performed. Results are compared with some ground measurements, and an analysis is made taking the land use classification as a basis. An accuracy close to 30 W m-2 is obtained.