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DEPOSITION VELOCITIES OF SO2 AND O3 OVER AGRICULTURAL AND FOREST ECOSYSTEMS
Citation:
Finkelstein, P L. DEPOSITION VELOCITIES OF SO2 AND O3 OVER AGRICULTURAL AND FOREST ECOSYSTEMS. Presented at Sixth International Conference on Air Surface Exchange of Gases and Particles, Edinburgh, England, July 3-7, 2000.
Impact/Purpose:
To improve the accuracy of emissions and dry deposition algorithms in the Agency's regulatory air quality and multimedia simulation models. This effort requires developing process-oriented algorithms, assembling geographical data, evaluating algorithms against field data, and designing and collaborating on field experiments to collect the data needed to test these algorithms.
Description:
The results of field studies that measured the flux and deposition velocity of SO2 and O3 are reported. Three of the studies were over agricultural crops (pasture, corn, and soybean), and two were over forest (a deciduous forest and a mixed coniferous - deciduous forest). In all cases the deposition velocity for SO2 was higher than that for O3. Diurnal cycles of SO2 deposition velocity were similar in shape, but not magnitude for all surfaces; however those for O3 showed some difference between forest sites where the peak was in the morning, and the agricultural sites where the peak occurred at mid-day. Seasonal cycles of SO2 were affected by deposition to surfaces when leaves weren't active, yet surface conductance is significant, but not for O3 where stomatal uptake is the primary pathway for deposition.