PERFORMANCE OF SOME EVAPOTRANSPIRATION EQUATIONS AT A SITE IN QUEBEC

Evapotranspiration (ET) estimates were made for a reference crop using the Modified Penman, Jensen-Haise, Baier-Robertson (Laval), FAO Blane y-Criddle, and SCS Blaney-Criddle equations. Results obtained from the five equations were compared to pan-based evapotranspiration data tak en from a site at St. Esprit, Quebec. On a seasonal basis, the Baier-R obertson (Laval) equation provided seasonal potential ET estimates wit hin 10% of adjusted pan evaporation values. The Modified Penman, FAO B laney-Criddle, and SCS Blaney-Criddle equations produced seasonal ET e stimates within IO to 25% of corrected pan ET data. The Jensen-Haise e quation consistently predicted lower seasonal values of ET, with an av erage seasonal difference of approximately 50% compared to the correct ed pan evaporation values. Seasonal ET estimates with the Baier-Robert son equation were not significantly different than corrected pan ET da ta at the 0.05 level of significance.