Estimativa dos componentes do balanço de energia e da evapotranspiração em plantios de eucalipto utilizando o algoritmo SEBAL e imagem Landsat 5 - TM.

Climatic variables are essential for understanding the environmental conditions that influence plant growth and development. In recent years research using climatic data and remote sensing techniques in spatial and temporal analyses of the demand for water and energy in plants has been intensified. SEBAL (Surface Energy Balance Algorithms for Land) is one of the most prominent algorithms for studies involving energy flow estimates in large areas, and it can be applied with few field measurements. This work, conducted in the municipality of Santa Bárbara, Minas Gerais state, Brazil, aimed at estimating energy balance components, and therefore the evapotranspiration in eucalyptus plantations by applying the SEBAL algorithm and Landsat 5 satellite's TM sensor image. Estimates have been made for a scene from day 06/20/2003. Considering only the areas related to the seven year-old eucalyptus plantations, average values of net radiation (Rn), soil heat flux (G), sensible heat flux (H) and latent heat flux (LE) of 420.12 W m-2, 81.80 W m-2, 149.93 W m-2, 188.39 W m-2 respectively were obtained. For actual hourly evapotranspiration (ETrh), the average value obtained was 0.28 mm h-1. The estimates are consistent with literature data, however, future studies with greater experimental control should be carried out