Actual evapotranspiration was determined in a rural catchment, "Hupselse Beek", situated in a sandy region in the eastern part of the province of Gelderland, in The Netherlands, the experiment covered a period of nearly 80 days in the summer of 1976, during which a severe drought was experienced in western Europe. Actual evapotranspiration was obtained indirectly by the energy budget on an hourly basis, in which the sensible heat flux was calculated from the mean temperature profile and the wind speed. The sensitivity of the results was analyzed for the choice of the roughness and the zero-plane displacement height in the wind profile, and for errors in the measured temperatures. The calculated results were quite insensitive to the exact formulation of the Monin-Obukhov functions for the mean wind and temperature profiles. However, it was found that the effect of non-neutral atmospheric conditions cannot be neglected; the effect of the buoyancy due to water-vapor stratification on the overall stability of the atmosphere was also noticeable. A comparison with a measure of potential evapotranspiration showed that the actual evapotranspiration was far from the potential.
|Journal||Journal of Hydrology|
|Publication status||Published - 1978|