The sensitivity analysis technique of models was applied to the data obtained from field experiment carried out during 2009 at Distillery Miriri, Capim, PB. This technique was applied to the reference evapotranspiration (ETo) by Penman-Monteith (FAO/56) and the sugarcane evapotranspiration (ETc) by energy balance equation based on Bowen ratio. The sensitivity analysis and errors were applied to the Bowen ratio method in measurement intervals of 15, 30, 60 and 120 min; however Penman-Monteith approach was applied on daily basis throughout the 2009 year. Results showed that the net radiation is the most sensitive variable in the energy equation balance and soil heat flux offers the lowest contribution. On the other hand, the relative errors for all variables in energy balance equation increase significantly with increase in sampling interval. The most sensitive variable in reference evapotranspiration by Penmam-Monteith method is net radiation, followed by relative humidity, wind speed at 2 m and air temperature.
energy balance; Penman-Monteith method; error analysis
