Hourly and Daily Reference Evapotranspiration with ASCE-PM Model for Paraná State, Brazil

Evapotranspiração de referência horária e diária pelo modelo ASCE-PM para o Estado do Paraná, Brasil

Abstract

The objective of this study was to verify the magnitude and trend of hourly reference evapotranspiration (ETo_h), as well as associate and analyze daily ETo (ETo_d) series and the sum of hourly ETo (ETo_24h) in 24 h, estimated with the Penman-Monteith ASCE model for Paraná State (Cfa and Cfb climate type). Relative humidity (RH), temperature (T), solar radiation (Rs) and wind speed (u₂) data were obtained from 25 meteorological stations from the National Meteorological Institute (INMET), between December 1, 2016 to November 8, 2018. The analyzes were performed by linear regression and associations considering the root mean square error, correlation coefficient and index of agreement. The ETo_h trend has a Gaussian distribution, with the highest values between 12:00 p.m. and 2:00 p.m., with the maximum average being 0.44 mm h⁻¹ (Cfa climate type) and 0.35 mm h⁻¹ (Cfb climate type). The average difference between the ETo_24h and ETo_d values was small (5.1% for Cfa and 7.4% for Cfb), resulting in close linear associations. The results obtained indicate that ETo_h has good potential to be used in planning and management in the field of soil and water engineering, in Paraná State.

Keywords:
hydrological cycle; water relations; water resources; models; precision