Evapotranspiração obtida por dados orbitais para o estado de Minas Gerais

Abstract

Evapotranspiration (ET) is one of the main components of the hydrological cycle and can be determined with the use of lysimeters, via water balance, or by empirical estimation methods that use surface weather data. The use of remote sensing data is prominent as alternative for estimating ET in regional scale. In this context, the objective of this work was to analyze the uncertainties of orbital products of evapotranspiration for the state of Minas Gerais, Brazil, during the year of 2014, using surface weather stations. The evapotranspiration products DMET and MOD16 were compared, with reference evapotranspiration estimates (ETo) calculated using the surface data of 35 meteorological stations of the Instituto Nacional de Meteorologia (INMET) network, and among each other. To evaluate the statistical performance, we considered: the Pearson correlation coeficiente (r), mean absolute error (MAE), mean percentage error (MPE) and root mean square error (RMSE). A strong linear correlation was verified in all comparisons, with the stations at Governador Valadares (r = 0.78), Lavras and Juiz de Fora (r = 0.80) and São Romão (r = 0.85) presenting the highest values for r. Furthermore, both the DMET and MOD16 products overestimated the evapotranspiration values along the analyzed period.