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Air-Surface Exchange
Research Programs
The interaction between the atmosphere and the underlying surface is increasingly recognized as important. A key output of atmospheric models for multimedia studies is the dry deposition component of total deposition (wet + dry). There is an extreme paucity of empirical dry deposition estimates for use with ecosystem management modeling. The estimates from the atmospheric models fill a critical gap.
Improved Dry Deposition for Network Applications
One of the ways the EPA assesses the results of air pollution control is through the Clean Air Status and Trends Network (CASTNET). In this task, we will continue development of better models for predicting deposition velocity for network operations. The model-predicted deposition velocity is then paired with the measured concentration to calculate the pollutant flux. Providing better estimates of deposition flux will improve our ability to forecast ecosystem sustainability.
Multimedia Modeling
Improved Dry Deposition Algorithms for CMAQ
The interaction between the atmosphere and the underlying surface is increasingly recognized as important. A key output of atmospheric models for multimedia studies is the dry deposition component of total deposition (wet + dry). There is an extreme paucity of empirical dry deposition estimates for use with ecosystem management modeling. The estimates from the atmospheric models fill a critical gap. A targeted focus on creating state-of-the-science dry deposition algorithms for the air quality models has significant importance to multimedia studies. This is an area of strong collaboration between Community Multiscale Air Quality (CMAQ) model development and the multimedia program. Two chemical species modeled using CMAQ that are of particular interest with respect to ecosystem effects and also have great modeling uncertainty are NH3 and SO2. Dry deposition of particles is also an important contributor to ecosystem loading. Recent field studies by Meyers of NOAA-Oak Ridge have shown surprisingly large deposition velocities for particles when compared to theoretical estimates. The work on this task will focus on improving our estimates of the dry deposition of these pollutants.