The objective of this work was to evaluate models to estimate net radiation and the Priestley-Taylor method in Dourados, in the State of Mato Grosso do Sul, Brazil. For the purpose, 1,421 daily observations of net radiation, global radiation, extraterrestrial radiation, and maximum and minimum air temperatures were used. Another database containing 360 of these same daily variables was used to independently test the models The reference evapotranspiration (ET0) was estimated by the Priestley-Taylor method as a function of global radiation. The estimated values of ETo were compared with 218 lysimeter data. The equation based only on the maximum and minimum air temperatures showed unsatisfactory performance. A mean performance was obtained with the model based on the extraterrestrial radiation and the maximum and minimum air temperatures. The models which included global radiation as independent variable had a more satisfactory performance. The Prietley-Taylor method showed very good performance and can be used to estimate the daily reference evapotranspiration in the region of Dourados from the solar radiation and the mean air temperature.
net radiation; solar radiation; reference evapotranspiration
