Probable reference evapotranspiration for Chapecó, Santa Catarina, Brazil

Evapotranspiration data are important for water resources management and irrigation design management. The present work aimed to determine the probable reference evapotranspiration Chapecó, Santa Catarina. Daily from 07/01/1973 11/30/2016 Chapecó meteorological station were used. was calculated using Penman-Monteith method grouped into pentads. average, maximum minimum values per pentad as well average dry rainy days determined. Beta probability distribution adjusted each goodness of fit evaluated with Kolmogorov-Smirnov test determination error, mean standard error estimate. Probable ETo determined 50, 75, 80, 90, 95% probability. monthly obtained 18 80% higher than those normally used in region, greatest differences occurring winter months. It is observed that vary 1.60 mm day-1 4.84 day-1. on 38% days. 75% presents 10 32% superior 50% probability, being bigger For projects it recommended use