Distribuição espaço-temporal do balanço de energia e da evapotranspiração utilizando o modelo METRIC

Abstract

Remote sensing techniques have been shown to be a useful tool for estimating physical phenomena at different time and space scales. The knowledge of evapotranspiration can be used in the planning and management of irrigation systems and water needed during the crop development cycle. In addition, this knowledge can help to manage water resources in basins that have conflicts. Bearing in mind that, in the Entre-Ribeiros basin, there is pressure on water resources due to the large concentration of irrigation systems, the METRIC model is an alternative to quantify water losses through evapotranspiration. This work objectified to obtain the energy balance components and, consequently, the daily evapotranspiration, with the METRIC model, in the Entre-Ribeiros basin. The methodology was developed in the following steps: i) Acquisition of Landsat 8 images, aspect, slope, and altitude in Topodata, as well as obtaining latitude from the DEM; ii) Obtaining meteorological data; iii) Obtaining variables to calculate the radiation balance and other components of the energy balance; iv) Implementation of the METRIC in Model Builder in ArcGIS; v) Calculation of components of the energy balance and daily evapotranspiration; and, vi) Comparison between the values of evapotranspiration obtained by METRIC and the crop evapotranspiration. It was observed that the model satisfactorily estimated the components of the energy balance (Rn, G, H, LE) and the daily evapotranspiration in the Entre-Ribeiros basin. Furthermore, the values obtained by METRIC, in comparison with field data, tended to overestimate in the analyzed months of the year 2017.