Estimativa da evapotranspiração de referência no município de Capim-PB.

Abstract

This study aimed to estimate the daily evapotranspiration of reference for the city of Capim-PB using the methods of empirical Penman, Penman-Monteith, Hargreaves and Samani, Linacre, Priestley-Taylor and Radiation. These methods were then correlated, according to each season, with the estimate of evapotranspiration reference of Class A tank method, used in Miriri Distillery and the Penman-Monteith, suggested by the United Nations Food and Agriculture Organization. For that were collected daily values of air temperature, relative humidity, solar radiation, atmospheric pressure and wind speed of automatic weather stations, 555ES model, installed in the company’s property previously mentioned in Capim II Farm, during the period from October 1st, 2005 to March 31st, 2008, which were recorded at intervals of 3 hours. Was found that the correlations of estimates referenced in this research with the Class A tank did not have good adjustments, besides obtaining low values of coefficients of correlation. In turn, the correlations made with the Penman- Monteith method were highlighted with the methods of Penman, Radiation and Priestley-Taylor whose coefficient more than 0.70, so that, in this case, it is suggested the use of the Radiation method equation to estimate evapotranspiration of reference in Distillery Miriri S.A., due to its dependence among the three, and even that of Penman- Monteith, which requires the least amount of meteorological data.