Evaluation of Methods of Estimation of Evapotranspiration of Reference (ETo) Daily for Regions of the States of Rio De Janeiro and Espírito Santo

Abstract The high consumption of water by agriculture makes knowledge about reference evapotranspiration (ETo) for irrigation management more and more essential. However, define an appropriate method to the different locations is associated with the availability of meteorological data and the adaptation of the methods to the application sites. Thus, the objective of this study is to compare and evaluate the performance of the ETo methods: Hargreaves-Samani, Jensen-Haise, Benavides & Lopez and Hamon using the standard method Penman Monteith FAO-56, to estimate the daily ETo of six regions, three of the state of Rio de Janeiro and three of the state of Espírito Santo. The meteorological variables employed were provided by the Center for Weather Forecasting and Climate Studies and the National Institute of Space Research - (CPTEC - INPE). The performance of the models was evaluated by different statistical techniques where the model that best suited the studied locations in the two states was the Jensen Haise, obtaining correlation indexes (r) between 0.73 and 0.94 and reliability (C) between 0.60 and 0.90 with the Penman Monteith model.