Evolução temporal da evapotranspiração de referência e sua sensibilidade aos principais elementos climáticos na cidade de Uberaba- MG

Abstract

The temporal evolution of the reference evapotranspiration (ETo) reflects the effects of the variables of the Penman-Monteith equation. Understanding the ETo behavior is fundamentally important to agriculture. Thus, the aim of this work was to analyze the effects of the possible climatological elements changes on the reference evapotranspiration in the region of Uberaba, Minas Gerais, Brazil, and to assess the sensitivity of the Penman-Monteith equation (FAO) to the variations of these climatic elements. Through tendency analysis, using the Mann-Kendall statistic and the t test of linear regression, the behavior of the following climate elements were analyzed: maximum and minimum temperatures; insolation; wind speed and relative humidity. Based on the Penman-Monteith model (FAO), the ETo was calculated and its changes were studied by analyzing the sensitivity of the ETo to the climatic elements and, also, the tendencies observed from these elements over the period from 1975 to 2003. There was an increase in the reference evapotranspiration, primarily due to the reduction of the relative humidity and the increasing wind speed. The reference evapotranspiration showed an increase of about 2.85 mm per year.