Evapotranspiração de referência para a Região do Cariri, CE: calibração e validação de modelos alternativos

Abstract

Reference evapotranspiration (ETo) is a fundamental meteorological variable for hydrological and agroclimatic planning in a region. Therefore, this work aimed to calibrate and validate alternative models for calculating reference evapotranspiration in the Cariri region of Ceará. To this end, a period of 3 years was used (2021-2023), with two years for calibration and one year for validation of the obtained coefficients. The FAO method (Penman‒Monteith) was used as a comparison standard for the methods of Hargreaves and Samani, Priestley-Taylor, Jensen-Haise and Blaney-Criddle. The performance of the methods was analyzed via statistical indicators, namely, the coefficient of determination, mean error, square root of the mean square error, Pearson's correlation coefficient, Willmont's accuracy index and the accuracy index described by Camargo and Sentelhas. The calibration of alternative ETo estimation models for the Cariri region of Ceará allowed more precise measurements. The adjusted Jensen-Haise and Preiestley-Taylor models presented more precise and accurate estimates and can be used, when necessary, to replace the FAO Penman–Monteith model. The Hargreaves-Samani and Blaney–Criddle methods were less accurate in estimating ETo.