Hourly reference evapotranspiration by Moretti-Jerszurki-Silva method using data from alternative station

Reliable measures of climate variables and the availability of alternative and safe methods are fundamental in estimating reference evapotranspiration (ETo) under unfavorable technical and financial conditions. The objective of this study was to evaluate the performance of the reference evapotranspiration estimation, in hourly periodicity, using the Moretti-Jerszurki-Silva models (ETo_MJS(ψair); ETo_{MJS(ψair;Ra)}), which considers air temperature (T) and relative air humidity (RH) data measured in an alternative station. The calibration and validation of the alternative station measurements were performed using data from automatic meteorological stations in Curitiba in Paraná (climate type Cfb) and Santa Rita de Cássia in Bahia (climate type Aw), Brazil. The use of the alternative station for hourly measurements of air temperature and relative air humidity in the analyzed climate types and locations were promising. The Moretti-Jerszurki-Silva models were robust in the analyzed locations, indicating satisfactory performance for the hourly periodicity. The Moretti-Jerszurki-Silva method that uses atmospheric water potential and solar radiation (ETo_{MJS(ψair;Ra)}) provided better adjustments and estimates of the hourly reference evapotranspiration, as opposed to the standard Penman-Monteith model.