Pixel-oriented land use classification in energy balance modelling

Mass and energy transfer between soil-vegetation and the atmosphere is the process that allows to maintain an adequate energy and water balance in the earth-atmosphere system. However, the evaluation of the energy balance components, such as the net radiation and sensible and latent heat fluxes, is characterized by significant uncertainties related both to the dynamic nature of heat transfer processes and surfaces heterogeneity. Therefore, a detailed land use classification and an accurate evaluation of vegetation spatial distribution are required for an accurate estimation of these variables. For this purpose, in the present paper, a pixel-oriented supervised classification was applied to obtain land use maps of the Basilicata region, in Southern Italy, by processing three Landsat TM and ETM+ satellite images. An accuracy analysis based on the overall accuracy index and the agreement Khat of Cohen coefficient showed a good performance of the applied classification methodology and a good quality of the obtained maps. Subsequently, these maps were used in the application of a Simplified Two-Source Energy Balance (STSEB) model for estimating the actual evapotranspiration at a regional scale. The comparison between the simulations made by applying the STSEB model and the measurements of evapotranspiration at a lysimetric station located in the study area showed the applicability and validity of the proposed methodology.