DAYTIME VARIATION OF SENSIBLE HEAT-FLUX ESTIMATED BY THE BULK AERODYNAMIC METHOD OVER A GRASS CANOPY

A study was performed to evaluate the bulk aerodynamic method for esti mating daytime variation of sensible heat flux (H-A) for a wetted and non-wetted grass canopy under clear and cloudy days. The aerodynamic r esistance applied was corrected for atmospheric stability using the Or egon State University One-Dimensional Planetary Boundary Layer model s tability function. The performance of the bulk aerodynamic method was tested with indirect measurements of sensible heat flux (H-B) derived from the Bowen ratio energy balance method on 20-min time intervals. R esults indicate that there was a good agreement between H-B and H-A wi th a coefficient of correlation of 0.93 and slope of the regression li ne through the origin of 0.96.