COMPARISON OF METHODS FOR ESTIMATING REFERENCE EVAPOTRANSPIRATION: AN APPROACH TO THE MANAGEMENT OF WATER RESOURCES WITHIN AN EXPERIMENTAL BASIN IN THE BRAZILIAN CERRADO

Abstract

ABSTRACT This study aimed to compare methods for estimating reference evapotranspiration using an experimental basin in the Brazilian Cerrado, for water management purposes. For that, we estimated daily reference evapotranspiration over a certain period (time series between 1982 and 2012) through different empirical methods. These methods consisted of Blaney-Criddle (BC), Hargreaves & Samani (HS), ASCE Penman-Monteith (ASCE- PM), Penman (1948/1963) (PO), Priestley-Taylor (PT), which were all compared to the standard Penman-Monteith FAO-56 (PM-FAO56). Based on statistics, ASCE- PM, P and BC methods should be recommended for cerrado areas, either in rainy or dry seasons. After these, the PT also stood out. Among the less complex methods, based on temperature and energy data, PT method is recommended whether climatological data are scarce either in rainy or dry seasons. Yet, HS reached the greatest errors, a broad data spread and low estimate accuracy, but showing better performance in dry periods, thus remaining under restricted use.

Keywords

• Evapotranspiration
• Methods
• Penman-Monteith FAO-56