Análise comparativa entre métodos de estimativa da evapotranspiração de referência (ETo) nas condições climáticas do município de Lavras-MG.

Abstract

They are enough estimates methods of reference evapotranspiration ETo, however, just some are more used and some developed in conditions Brazilian, but little known, being part of these methods accepted, other criticized and until despised. The diversities of results reached by the different methods have been causes of the researcher`s concern, that is, which method esteems ETo correctly. As well as, the absence of certain meteorological variables registered in the irrigated areas it can carried out the technicians to use simpler methods, certainly, another method that involves additional data it could supply more representative results of the reality. Like the Penman-Monteith- FAO (PM-FAO) method for estimate ETo need a great number of meteorological elements, this work was carried out to evaluate the correlation among different methods used in determination of ETo. The Hargreaves-Samani and Jesen-Haise methods were the most suitable for the estimate of ETo. The Tanque Classe A method in spite of low precision presented high accuracy. The Blaney-Criddle and Thornthwaite methods were not adjusted satisfactorily for the estimate of ETo in the daily scale. The methods Penman-1963, Penman-FAO and Penman-FAO-Combinado, were that presented the best results, however these methodologies are plenty similar to PM-FAO.