AVALIAÇÃO DE DIFERENTES METODOLOGIAS DE ESTIMATIVA DA ETo BASEADAS NO TANQUE CLASSE A, EM MOSSORÓ, RN

Abstract

The reference evapotranspiration (ETo) by Class A pan (TCA) is an indirect method and widely used in Brazil because of its low cost and easy handling. This work it had as objective to determine, for differ- ent methodologies of determination pan coefficients (Kp) that they are proposed in literature, the ETo gotten with the aid of the evaporation Class A pan (ECA), and to compare such results of ETo of Class A pan with the ETo estimated by the FAO Penman-Monteith method which is considered the standard fort the FAO, with his- torical series data of 15 years. There was a good performance of the Class A pan method to estimate the monthly values of ETo, considering the different ways of calculating Kp, and the methodology proposed by Snyder showed the highest rate of concordance (d = 0.80475) and lower mean absolute error (MAE = 0.28452 mm day-1), indicating its potential for practical use on the estimating of daily ETo in the region of Mossoró, Rio Grande do Norte, Brazil.