1B.1 The Atmospheric Chemistry and Canopy Exchange Simulation System for Ammonia (ACCESS-NH3): Formulation and Application to Measurements from a Deciduous Forest Canopy

Monday, 8 January 2018: 8:45 AM
Room 18CD (ACC) (Austin, Texas)
Rick Saylor, NOAA, Oak Ridge, TN; and Z. Wu, J. T. Walker Jr., X. Chen, D. B. Schwede, and A. C. Oishi

As nitrogen oxide and sulfur dioxide emissions decrease in the U. S. as a result of air quality regulations, ammonia (NH3) is being recognized as playing an increasingly important role in fine particle (PM2.5) formation. If regulations on NH3 emissions are implemented in the future, it will be necessary to have reliable models of NH3 bi-directional exchange over a variety of land use types to help formulate effective control or mitigation strategies. The Atmospheric Chemistry and Canopy Exchange Simulation System for Ammonia (ACCESS-NH3) is a multilayer, single column model that simulates the bi-directional transport and exchange of ammonia throughout the soil-plant-atmosphere continuum. In this presentation, the ACCESS-NH3 modeling system is described and results from its application to a deciduous forest canopy are presented. NH3 concentration and flux measurements, along with micrometeorological and environmental observations, were made within and above a forest canopy at the U. S. Forest Service’s Coweeta Hydrologic Laboratory in southwestern North Carolina during the summer of 2015. ACCESS-NH3 has been applied to the data obtained during this field experiment to evaluate the model and to assess how NH3 interacts with a deciduous forest canopy and how these interactions vary as a function of environmental conditions. Results from these evaluations and simulations will be presented.
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