Estimativa da evapotranspiração real no semiárido da Bahia usando geotecnologias.

Abstract

Evapotranspiration is an important component of the hydrological cycle and its quantitative information is essential for the sustainable management of water resources. In this work, the algorithm (Surface Energy Balance Algorithm For Land) was used to estimate the energy balance components (G, H, LET) and the regional scale real evapotranspiration (ETr) for the dates: 01/30/2019, 09/27/2019, 01/02/2009, 09/15/2009, 07/01/1999, 09/04/1999, 01/22/1987,09/19/1987. The study was carried out in the Jacaré river basin in the semiarid state of Bahia, notably in the Irecê microregion. Reference evapotranspiration (ET0) obtained by the Penman-Monteith method was used to calibrate the SEBAL algorithm. Sensitive heat flux, ground, latent, NDVI, SAVI, IAF maps were generated. The results showed absolute and relative errors for the date of 01/02/2009 of up to 7.21 mm day-1 and 51, 68% respectively for the months of January. Still the smallest errors found were for the date of 01/22/1987 being the Absolute Error equal to 8.77 mm day-1 and 16.08%. The errors found are due to the precipitation preceding the study dates and the subjectivity of the choice of hot and cold pixels. However, for September, good results were found, showing errors Absolute error equal to 0.06 mm day-1 and Relative Error, 1.21% for the date of 04/09/1999, being the largest errors found for this month being equal to Absolute Error, 0.15 mm day-1 and 3.04% for the date of 19/09/1987. However, for September, good results were found, showing errors Absolute error equal to 0.06 mm day-1 and Relative Error, 1.21% for the date of 04/09/1999, being the largest errors found for this month being equal to Absolute Error, 0.15 mm day-1 and 3.04% for the date of 19/09/1987. The IDW statistic did not lend itself to reducing absolute and relative errors. Despite the disparity of errors between January and September, the SEBAL algorithm can be used as a tool to generate subsidies for water resources management.