Technique for Estimation of Dry Deposition Velocities Based on Similarity withLatent Heat Flux

摘要

Field measurements of chemical dry deposition are needed to assess impacts andtrends of airbrone contaminants on the exposure of crops and unmanaged ecosystems as well as for the development and evaluation of air quality models. This paper describes an intermediate technique which can give accurate estimates of dry deposition velocity for chemical species which are dominated by stomatal uptake such as ozone and SO2. This method can give results that are nearly the quality of eddy correlation measurements at much lower cost. The concept is that bulk stomatal conductance can be accurately estimated from measurements of latent heat flux combined with standard meteorological measurements of humidity, temperature, and wind speed. The technique is tested for a field experiment where high quality eddy correlation measurements were made in a soybean field in Kentucky. Over a four month period, which covered the entire growth cycle, this technique showed very good agreement with eddy correlation measurements for ozone.