EVAPOTRANSPIRATION ESTIMATION IN A CENTRAL PIVOT LOCATED IN RIO PRETO BASIN – BRAZIL: COMPARISON BETWEEN BOWEN RATIO METHOD AND SEBS

Water management in Brazil is based on economic instruments, regulation (command-and-control) and regulatory practices that include permits for water withdrawals and enforcement. Enforcement activities are related to information gathering on actual water uses and verification of water permit conformity. One way of obtaining information about water consumption is through the use of remote sensing data, particularly the mapping of irrigated areas and the estimation of actual evapotranspiration with its inference on water withdrawals. The objective of this work was to evaluate the SEBS model – Surface Energy Balance System for estimating actual evapotranspiration of irrigated beans in a central pivot located in Rio Preto Basin (Brasilia – Brazil). The results show that SEBS is very sensitive to the quality of input data, particularly air and surface temperature. Successive corrections of surface temperature (atmospheric correction and calibration with in-situ data) were beneficial for simulated λE and ET output.