Estimativa da evapotranspiração potencial provável em Divinópolis, MG, Brasil

Abstract

Evapotranspiration (ET) is a fundamental variable to estimate the water requirement of a given region, especially when it comes to planning or developing systems that involve water management, with the probable ET being the depth of this that can be matched or overcome at a certain level of probability.  us, the objective of this study was to estimate the monthly probable potential evapotranspiration (ETp) of the city of Divinópolis, MG, from the veriĕ cation of non-parametric statistical distributions that best represents the historical series of monthly ETp for the city. For this, the daily data collected from a conventional meteorological station of the Instituto Nacional de Meteorologia were analyzed, for a series of 13 years (2003 to 2015).  e Gumbel for Maximum, Fréchet, Gama, Log-Normal 2P and Beta frequency distributions were adjusted to the observed series, and the ĕ ttings of these models were tested by the Kolmogorov-Smirnov and Chi-Square methods, both at 5% probability.  e probable monthly ETp was calculated for frequencies of 90%, 75%, 50%, 25% and 10%.  e Beta distribution was the one that best ĕ tted to most series of monthly potential evapotranspiration, and the worst ĕ t was obtained with the Log-Normal distribution with 2 Parameters.  e maximum probable monthly ETp for Divinópolis is 153.92 mm, associated with a 10% probability of occurrence for the month of December, while the lowest is 101.32 mm, with a 90% probability of occurrence in the month of June.