Standardized Referente Evapotranspiration Equation

Abstract

IN THIS PAPER IS PRESENTED A DISCUSSION ON THE NECESSITY TO STANDARDIZE THE PENMAN-MONTEITH EQUATIONS IN ORDER TO ESTIMATE ETO. THE PROPOSAL IS TO DEFINE AN ACCURACY AND STANDARIZE EQUATION BASED IN PENMAN-MONTEITH. THE AUTOMATED WEATHER STATION NAMED CIANO (27° 22' 14 4 NORTH LATITUDE AND 109° 55' WEST LONGITUDE) IT WAS SELECTED TO MAKE COMPARISONS. THE COMPARED EQUATIONS WE RE: A) CIANO WEATHER STATION, B) PENMAN-MONTEITH ASCE (PMA), PENMAN-MONTEITH FAO 56 (PM FAO 56), PENMAN-MONTEITH ESTANDARIZADO ASCE (PM STD. ASCE). THE RESULTS WERE: A) THERE ARE IMPORTANT DIFFERENCES BETWEEN PMA AND CIANO WEATHER STATION. THE DIFFERENCES ARE ATTRIBUTED TO THE NON STANDARDIZATION OF THE EQUATION CIANO WEATHER STATION, B) THE COEFFICIENT OF CORRELATION BET WEEN BOTH METHODS WAS OF 0,92, WITH A STANDARD DEVIATION OF 1,63 MM, AN AVERAGE QUADRATIC ERROR OF 0,60 MM AND ONE EFFICIENCY IN THE ESTIMATION OF ETO WITH RESPECT TO THE METHOD PATTERN OF 87%.