Meteorological Variables Influence Analysis Over Petrolina-Juazeiro Pole Monthly Reference Evapotranspiration

This paper intends to quantify the influence of the meteorological variables maximum and minimum temperature, maximum and minimum relative humidity, atmospheric pressure, wind velocity and solar radiation on the reference evapotranspiration, ETo, according to the Penman-Monteith equation of the FAO-56 bulletin. The meteorological data was obtained from an automatic meteorological station on the period from 2007 to 2010 located in Petrolina-PE, latitude -9,38 degrees, longitude -40,80 degrees and 370,50m above sea level. This influence was calculated based on the signal table method for 2<^>7 factorial experiment. The experiments showed that maximum temperature, minimum relative humidity, wind velocity and solar radiation were the most influent factors on the study, influencing on average 7,49%, 8,37%, 32,58% and 46,67% of the ETo monthly variation, respectively.