The performance of the methods for estimating reference evapotranspiration (ETo) varies depending on the local climate. Therefore, this study aimed to: a) assess the performance of the indirect method of ETo estimation, on the daily and monthly scale, for the period from October to March, b) verify the quality of the methods for use in viticultural zoning studies for calculation of Dryness Index (DI), both having as standard method the Penman-Monteith-FAO. Daily meteorological data were used from October to March, in 1961 to 2010 period, from the network of meteorological stations FEPAGRO and INMET located in Campanha, RS. The evapotranspiration was calculated by the methods of Thornthwaite, Camargo, Makkink, Solar Radiation, Jensen-Haise, Linacre, Hargreaves-Samani, Blaney-Criddle and Penman-Monteith, later determined the DI, comparing them with those obtained by Penman-Monteith. It was found on the daily scale that ETo showed differences in performance between the methods, varying the classification of "poorly" to "very good". On a monthly scale, methods that performed best had a performance rated as "good," for methods of Solar Radiation, Makkink, Blaney-Criddle and Camargo. For the dryness index in March, it turns out that the methods of Thornthwaite and Camargo showed great performance, being methodologies that can be adopted to estimate evapotranspiration for DI in the Geoviticulture Multicriteria Climatic Classification System for Campanha, RS.
Penman-Monteith; empirical methods; reference of evapotranspiration; Geoviticulture Multicriteria Climatic Classification (MCC) System
