Estimativa da evapotranspiração de referência para a cidade de Areia, Paraíba

Abstract

One way to calculate the depth of fluid to be applied to plants through irrigation, using the estimated value of the reference evapotranspiration (ET0). For such an estimate is used several models aimed at reducing the scope for errors and consequent saving water and energy during production process, and these values, fundamental information for the calculation of irrigation. Thus, this study aimed to estimate the reference evapotranspiration (ET0) for the Areia County, Paraíba State, Brazil, via the methods proposed by Hargreaves-Samani, Blaney-Criddle and Priestley-Taylor, and compare the results with the value estimated by the model proposed by Penman-Monteith, considered by FAO. Data collection was performed at the Laboratory of Meteorology and Climatology of DSER/CCA/UFPB, Areia, PB, used a weather station, the variables were: relative humidity, maximum and minimum temperatures of air, sunlight and wind speed. These data were collected daily during the period from 1998 to 2007, such values being submitted to the Reference Evapotranspiration Calculation Software (REF-ET) and the monthly averages calculated for determining estimates of evapotranspiration. It was concluded that the model of Priestley-Taylor showed good correlation with the standard Penman-Monteith, with an R 2 equal to 0,980 and Blaney-Criddle model showed the worst performance among the models studied.