Contribution to the Study of Regional Actual Evapotranspiration with the Use of Surface Energy Balance and Remote Sensing for Central Greece

Abstract

Actual Evapotranspiration (ETa) is one of the main components of the hydrologic cycle and a continuous effort arises in order to improve its estimation. In this study in-situ data from selected meteorological stations over central Greece are used to calculate daily ETa values during the warm season. These values then are combined with ETa values computed with SEBAL (Surface Energy Balance Algorithm for Land) method. SEBAL is an image-processing model comprised of 25 computational submodels that computes ETa and other energy exchanges as a component of energy balance. A series of Landsat-7 Enhanced Thematic Mapper Plus (ETM+) satellite images were acquired and used for the estimation of ETa on a pixel-by-pixel basis. Landsat images consist of eight spectral bands with a spatial resolution of 30 m for Bands 1--7. ETa values generated from two different sources are then analyzed and annotated. Finally ETa values are mapping provided a useful and efficient tool for the estimation of regional actual evapotranspiration used for water resources and irrigation scheduling and management.