The authors calibrated the dryoff of sensors in the lab and derived a resistance value of 900 kOhm. Under field conditions this value was found to underestimate dew duration by an average of 1.5 hrs, whereas the field derived threshold of 6999 KOhms underestimated dew duration by an average of 0.3 hrs. The most common suggestion for standardization is the adoption of a specific sensor design as the standard. The protocol specified the placement of sensors inside an evergreen bush. As a consequence, there is no universal standard for wetness measurement.
Water is added to a budget by precipitation or condensation from dew and lost by evaporation.
A surface energy balance model can describe these physical processes as a balance of energies. For example during a dew event, radiant energy is lost from the plant surface and is converted into latent and sensible heat. The latent heat flux effects evaporation and condensation, while sensible heat flux affects the heat losses and gains at a leaf surface. The partition of radiation into latent and sensible heat depends upon the atmospheric conditions and the plant and soil physical properties. A theoretical standard offers many advantages.