Estimativa da evapotranspiração real pelo modelo METRIC parametrizado em áreas irrigadas no semiárido brasileiro.

Abstract

The estimate of real evapotranspiration is a valuable quantification in irrigation management, in order to maximize the efficient use of water and energy resources. Algorithms have been gaining prominence in estimating real evapotranspiration, due to greater accuracy, speed and low cost. In this context, the objective will be to evaluate the parameterization of the METRIC model in estimating real evapotranspiration using spectral data from Landsat-8 satellite images and meteorological data, and compare it with the standard reference method in two irrigated areas in the Brazilian semi-arid region. The ETa will be estimated from the latent heat flux density, obtained as energy balance residue by the parameterized METRIC model, which includes in its implementation radiometric calibration, computation of reflectance and biophysical variables, radiation balance, heat flux in the soil and parameterized iterative processes to obtain sensible heat. Considering the results found in the present research with the new methodological procedure of the Parameterized METRIC algorithm, it can be concluded that the model constitutes a promising tool to obtain the current evapotranspiration of crops on a regional scale, in addition to being a practical, economical and efficient tool in generation of subsidies for the proper management and decision-making of water resources, as long as the technical norms required for using the model are obeyed, mainly with regard to the characteristics of the area to be studied