A study was performed at the Panguilemo Experimental Station located in Talca (VIIth Region of Chile) to evaluate daytime variation of tomato evapotranspiration by using the residual energy balance method (ETRE) over tomato canopy under clear and cluody days. Furthermore, models for estimating sensible heat flux, soil heat flux and net radiation were evaluated and calibrated for the Panguilemo site. Data collected included air temperature, surface temperature, air vapor pressure, wind speed, incoming solar radiation, soil heat flux and latent heat flux.
The performance of the residual energy balance method was tested with evapotranspirationmeasured from the Bowen ration method (ETB). Results indicate that ETRE compared very well with ETB under varied atmospheric conditions with an overall standar error of estimate of 40 W/m2 and absolute error of 7 %.