Calibration of the Penman-Monteith method to estimate latent heat flux over a grass canopy

A study was performed at the Panguilemo Evapotranspiration Investigation Plot (ETIP) located 11 km north of Talca, Chile (35 degrees 23' South and 71 degrees West; 110 m above the sea level) to evaluate latent heat flux by using the Penman-Monteith method. Data collected on a 20 minute time intervals included latent heat flux (LE), net radiation (Rn), soil heat flux (G), air temperature (Ta), relative humidity (RH), and wind speed (V). The performance of the Penman-Monteith equation (LEPM) was tested with latent heat flux measurements from the eddy correlation system (LEED) over a grass canopy under different soil moisture conditions. Results indicate that there was a good agreement between LEPM and LEED with an overall standard error of estimate (SEE) of 45 W.m(-2) and an absolute relative error of 6.2 %.