Energy balance model as real evapotranspiration estimator with satellite and meteorological data

SEBASTIAN GAVILAN; JUAN IGNACIO PASTORE; IGNACIO QUIGNARD; DAMIÁN MARASCO; PABLO ACEÑOLAZA

INTERCIENCIA

INTERCIENCIA

Lugar: Caracas; Año: 2019 vol. 44 p. 400 - 407

0378-1844

Evapotranspiration (ET) is the process whereby water present in the soil is transferred to the atmosphere as vapor. ET is one of the most important fluxes in the hydrolog¬ical cycle, with estimates of more than 60% of precipitation returning to the atmosphere through ET. Different methods based on weather information have been used to estimate reference ET (ET0), but they provide regional nature esti¬mates, since ET0 expresses only the evaporating power of the atmosphere. The ET that actually takes place from a given plant cover is known as real ET (ETR) and its estimation is usually more complex since it requires information about the current state of the vegetation. Satellite information is an attractive tool to obtain data on vegetation and soil moisture, which can be complemented with meteorological information. This paper proposes and evaluates an energy balance model to calculate ETR using data from satellite imagery and mete¬orological stations. The model is based on SEBAL (surface energy balance algorithm for land), which was modified for automatically selecting/classifying pixels by thresholds. The generated model was tested in two typical wheat/soy bean farming areas of Argentina. The results showed an appropri¬ate segregation of the dominant soil cover types and a high concordance of obtained data with those present in the liter¬ature.