Utilizing Sevap Software to Estimate the Reference Evapotranspiration on the Minas Gerais State

Abstract

Reliable estimates of reference evapotranspiration (ET0) are necessary to address different aspects related to the management of water and environmental resources. There are several models for estimating ET0, each designed for different climatic conditions and which require review before being used in the new region. Given this, we aimed to compare different methodologies for estimating ET0 in different seasons in Minas Gerais State. The methodologies tested were Hargreaves-Samani, Jensen-Haise, Linacre, Makkink and Priestley-Taylor. Estimates of ET0 were held in different annual season (spring, summer, autumn and winter). The meteorological data needed to perform this work were taken from Standard Climatological (1961-1990) of 50 localities of Minas Gerais, provided by the National Institute of Meteorology (Inmet). The method was taken as the standard Penman-Monteith-FAO56 and comparison of results was by the coefficient of determination (r²), the coefficients "a" and "b" of the linear regression equations, standard error of estimate (ESE), Willmott index of agreement (d), the Pearson correlation coefficient (r) and confidence coefficient (c). Independent of the season the Jensen-Haise and Makkink methods should not be use to estimate of ET0 in Minas Gerais State. On the winter, the