Análise da evapotranspiração de referência a partir de medidas lisimétricas e ajuste estatístico de estimativas de nove equações empírico-teóricas com base na equação de Penman-Monteith / Analysis of the reference evapotranspiration from lysimetric data and statistical tuning of nine empiric equations based on the Penman-Monteith equation

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The quantification of the evapotranspiration is an essential task for the determination of the water balance in a watershed and for the establishment of the culture´s water deficit. Therefore, the present work describes the analysis of the reference evapotranspiration (ETo) for the region of Jaboticabal-SP. The phenomenon behavior in the region was studied based on the interpretation of 12 drainage lysimeters data (EToLis) and on theoretical estimates for 10 different equations available in the Literature. An statistical analysis indicated that the theoretical ETo estimates compared with the EToLis did not present good indices of comparison and error. Admitting that the lysimeters operation did not allow a reliable ETo determination, a local adjustment of the theoretical methodologies for ETo estimate was considered. An auto-regression (AR) of the noises of these equations in comparison with the annual average estimate for the Penman-Monteith equation (EToPM), taken as standard, has been performed in fortnightly and monthly periods. The adjustment through simple linear regression has also been analyzed. The obtained results indicate that the effective radiation is the most important climatic variable for the establishment of the ETo in the region. The Penman-Monteith estimate presented excellent correlation to the estimates by Makkink (1957) equation and the energy balance. The local adjustments presented excellent results for the majority of the tested equations, specially for the solar radiation FAO-24, Makkink (1957), Jensen-Haise (1963), Camargo (1971), radiation balance, Turc (1961) and Thornthwaite (1948) equations. The adjustment by simple linear regression is of easier execution and also presented excellent results.

ASSUNTO(S)

auto-regressão evapotranspirometer penman-monteith auto-regression lisímetro lysimeter penman-monteith evapotranspirômetro linear regression regressão linear

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