Estimation of common bean (cultivar BRS Estilo) crop evapotranspiration by remote sensing using different albedo sources

Evapotranspiration (ET) estimation by remote sensing is an innovative and promising option, due to its low cost and operation. It is an important tool for estimating ET and can be used to support decision-making. The origin and quality of images are fundamental for quality of information, as low spatial and temporal resolution of satellites directly impacts these customers. In this context, the objective of this study was to estimate the evapotranspiration of common bean crop using the SAFER algorithm in three different sources of albedo. The study was carried out in a bean cultivation area irrigated by central pivot, located in Itaberaí-GO Brazil in 2021. Images from a MicaSense Altum multispectral and thermal camera coupled to a drone and albedo images from Landsat 8 and Sentinel 2A satellites were used for ETa estimation. The data were compared with ET met by FAO method, Embrapa and climatological water balance by statistical indices. The correlation with standard methods was satisfactory, especially with FAO, and in general, the MSE (mean square error) and MAE (mean absolute error) adopted values smaller than 0.4mm day-1. The confidence index ranges from 0.91 to 0.97. The comparison of the ET values calculated from the multispectral and thermal camera and the three ways of calculating the surface albedo was considered satisfactory. Thus, the adaptation adopted in the SAFER algorithm for obtaining the albedo was efficient. The use of multispectral and thermal camera images with SAFER is an efficient tool in estimating the evapotranspiration of bean crop, and is capable of replacing the use of orbital images, which are limited by meteorological conditions and imaging frequency.