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DRY DEPOSITION OF POLLUTANTS TO FORESTS
Citation:
Finkelstein, P L., T G. Ellestad, J F. Clarke, AND T. P. Meyers. DRY DEPOSITION OF POLLUTANTS TO FORESTS. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 13-17, 1999.
Impact/Purpose:
This task has the following objectives:
Improve modelers' ability to focus on scientific and policy issues in modeling studies by providing software that supports composing, applying, and evaluating complex systems of models.
Improve the understanding of the interaction of the atmosphere and the underlying surface, especially the flux of mass in both directions, and EPA's ability to simulate that interaction.
Contribute to multimedia studies and assessments by applying state-of-the-art atmospheric models, estimating atmospheric contributions to multimedia issues and the sources of those contributions, and evaluating the models' strengths and weaknesses.
Description:
We report on the results of an extensive field campaign to measure dry deposition of ozone and sulfur dioxide to a sample of forest types in the United States. Measurements were made for full growing seasons over a deciduous forest in Pennsylvania and a mixed deciduous-coniferous forest in New York, as well as a month long series of measurements over a pine plantation in North Carolina. Seasonal and average diurnal patterns of flux and deposition velocity, as well as the effects of sunlight, plant growth rate, and surface moisture are reported and contrasted for each pollutant. The differences in deposition velocity between ozone and sulfur dioxide deposition velocity are attributed to their different surface resistances, recognizing that ozone is taken up almost exclusively through the stomata while sulfur dioxide may be deposited on the plant cuticle and other surfaces. Observations are compared with the Meyers Multi-Layer Deposition Velocity Model. The strengths of the model are noted, as are the opportunities for improvement.