Abstract

Abstract The two-layer model of Shuttleworth and Wallace (SW) was evaluated to estimate transpiration (Tsw) from a drip-irrigated olive (Olea europaea L. 'Arbequina') orchard, located in Pencahue Valley, Maule Region of Chile (35° 23' LS; 71° 44' LW). An automatic weather station was installed in the center of the orchard to measure air temperature, relative humidity, wind speed, latent heat flux, net radiation and soil heat flux from October to December 2010. Values of Tsw were compared with sap flow measurements on 30-minute time interval. Results indicated that model was able to predict olive transpiration with a root mean square error (RMSE) of 22 W m-2 and a mean absolute error (MAE) of 18 W m-2. On a daily basis, the model was able to predict the olive transpiration with RMSE and MAE values of 0.51 and 0.41 mm d-1, respectively. In general, the model tended to underestimate transpiration with errors less than 12 and 17% on 30-minute and daily basis, respectively.