Remote sensing and empirical models in the estimation of reference evapotranspiration in a semi-arid region - DOI: 10.7127/rbai.v1901389

Resumo

Correct estimation of reference evapotranspiration (ETo) values is of paramount importance for water management at basin level as well as in agricultural production areas. The objective of this study was to compare ETo estimates obtained by means of remote sensing and empirical mathematical models for the Cariri region, CE, Brazil. Remote sensing data were obtained using the MOD16A2 product (8 days) of the MODIS instrument. Raster images were obtained with a resolution of 500 x 500 m, downloaded from the Earth Explorer website. ETo was calculated with terrestrial data by the Penman-Monteith-FAO method and by the alternative models of Hargreaves and Samani, Jensen and Haise, and Makkink. The period evaluated was from 2021 to 2022. The evaluation of the results was based on statistical parameters. ETo data obtained through satellite images showed low accuracy and a high tendency to overestimate the values calculated by the Penman-Monteith-FAO model. The Makkink model proved to be accurate in the ETo estimates, and can be used, when necessary, to replace the standard Penman-Monteith-FAO model.