Comparison of safer and metric-based actual evapotranspiration models in a subtropical area of Brazil


Remote sensing algorithms are well known to estimate surface energy fluxes in regional to global scales with low cost. Accurate measurements of actual evapotranspiration (ET) in regional scales for crops are demanded for a better calculation of water management scenarios. The remote sensing approach has an advantage of estimating ET from larger spatiotemporal scales when compared with traditional methods. This study compared the result of ET estimates from the “Simple Algorithm for Evapotranspiration Retrieving” (SAFER) and “Mapping Evapotranspiration at high Resolution with Internal Calibration” (METRIC) models on varied land uses of a subtropical area located in Southeast Brazil by using LANDSAT-8 satellite data. Meteorological data collected from an agrometeorological station was used for giving input to both models. The results showed similarity of ET estimate from both models, although slight deviation especially at high ET values. It happened due differences as the need of anchor pixel in METRIC, which requires two points with extrem thermohydrological conditions in the same area. Minimum ground data requirement is the major advantage of the METRIC over the SAFER model. SAFER requires high quality weather data from the ground station located inside the study area, and for this reason can take into account the daily variability of climatic parameter. The maximum value, the sum and ET range by METRIC was higher than SAFER. Nevertheless, the study has considered both models feasible for estimation of ET from satellite data in the study area.

SILVA, César de Oliveira Ferreira; MANZIONE, Rodrigo Lilla; ALBUQUERQUE FILHO, José Luiz. Comparison of safer and metric-based actual evapotranspiration models in a subtropical area of Brazil. In: INOVAGRI INTERNATIONAL MEETING, 5., CONGRESSO NACIONAL DE IRRIGAÇÃO E DRENAGEM, CONIRD, 25., SIMPÓSIO LATINO AMERICANO DE SALINIDADE, 1., 2019, Fortaleza. Anais… 4 p.

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