AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
An Investigation of Secondary Organic Aerosol Precursors and Formation Processes in and above Deciduous Forest Canopies
RICK SAYLOR, Ariel Stein, NOAA Air Resources Laboratory
Abstract Number: 88 Working Group: Remote and Regional Atmospheric Aerosols
Abstract The deciduous forest canopies of the southeastern U. S. are significant emission sources of biogenic volatile organic compounds (BVOCs) and have the potential to significantly influence the formation and distribution of secondary organic aerosol (SOA) mass in this region. The biogenically-derived SOA formed as a result of emissions from the widespread forests in the southeastern U. S. can affect air quality in populated areas, degrade atmospheric visibility throughout the region, and may also affect regional climate through both direct and indirect forcings. In an effort to better understand the formation of SOA mass from forest emissions in this area, a 1-D column model of the physical and chemical processes occurring within and just above a deciduous forest canopy has been created. This model, the Advanced Canopy Chemistry and Exchange Simulation System (ACCESS), includes processes accounting for the emission of BVOCs from the canopy, turbulent vertical transport within and above the canopy, detailed chemical reaction, mixing with the background atmosphere and deposition to the canopy and forest floor. In this presentation, the model formulation will be described and results will be presented investigating the canopy concentrations and fluxes of gas-phase precursors of SOA and how those concentrations may be affected by background anthropogenic nitrogen oxides (NOx) and VOCs and by biogenic NOx emitted at the surface. The model results will be used to estimate how well current 3-D air quality and atmospheric chemistry models account for the complex physical and chemical processes occurring within forest canopies and if a more complete parameterization of these processes is required for improved SOA simulations from these models.