Abstract
The determination of crop evapotranspiration (ETc) values is very useful information for planning irrigation, water supply estimation, regulation of water rights and river basins hydrologic studies. Values of ETc in the North region of Minas Gerais state, Brazil, were estimated in this research from the multispectral images of the Landsat 5 TM by means of the model Surface Energy Balance Algorithm for Land- SEBAL, based on the simplified energy balance equation of a surface covered by vegetation, using a few daily surface climatological parameters (wind speed, rainfall, air temperature and relative humidity, solar radiation). The aim of this study was to estimate the regional spatial distribution of the energy balance components and evapotranspiration in the study area, covering the irrigated perimeter of Gorutuba, involving the cities of Nova Porteirinha, Janaúba, Porteirinha, Verdelândia and Pai Pedro. Thematic maps of regional evapotranspiration and energy balance components were generated from spectral analyzes of the images obtained, associated with the used weather data. The ability of SEBAL to provide the spatial variability of energy balance components, including evapotranspiration, demonstrated its sensitivity to different occupation of the soil surface vegetation, and to high data temporal and spatial resolutions data, indicating that the SEBAL model can be used in scales and operational routine for north region of Minas Gerais.
