Performance of the SEBAL and SSEBop Models in the Estimation of Wheat Evapotranspiration in the Cerrado

Abstract

The growth of the irrigated area in the Cerrado affects the volume of water captured in the hydrographic basins, directly influencing the availability and allocation of water resources. In basins with predominance of irrigated agriculture, it is essential to understand the spatio-temporal variation of the real evapotranspiration of a crop (ETR), for a more assertive planning and management of the reservoirs. Considering the wheat cultivation potential in the Cerrado, the study aims to estimate the crop's water demand in the 2018 and 2019 harvests, using the SEBAL and SSEBop models. Compared to the Bowen ratio method, SEBAL presented R² variations between 0,86 and 0,72, and its performance was classified as satisfactory. The RMSE determined was 0,50 mm d⁻¹ in 2018 and 0,42 mm d⁻¹ in 2019. The SSEBop model expressed better performance in both seasons, with R² variability between 0,95 and 0,78, representing more adequately the ETR with lower RMSE, of 0,25 mm d⁻¹ and 0,41 mm d⁻¹, corresponding to the 2018 and 2019 cycles. The simplified configuration of the SSEBop and the good performance under the conditions verified, make the model an appropriate tool, which can contribute to an efficient water planning in the region.

Keywords
energy balance; remote sensing; Bowen Ratio