HR: 12:05h
AN: A52B-07    [Abstracts]
TI: Impact of Aromatics, Terpenes, and Additional Organic Nitrates on Global Tropospheric Chemistry
AU: * Ito, A
EM: akinorii@umich.edu
AF: Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward, Ann Arbor, MI 48109-2143 United States
AU: Sillman, S
EM: sillman@umich.edu
AF: Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward, Ann Arbor, MI 48109-2143 United States
AU: Penner, J E
EM: Penner@umich.edu
AF: Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward, Ann Arbor, MI 48109-2143 United States
AB: Aromatics, monoterpenes, and ethene are sometimes regarded as relatively unimportant to tropospheric chemistry. These species and their reaction products are sometimes omitted from global chemistry/transport models [e.g., {\it Bey et al.}, 2001] or else are represented in approximate form. Here, we show the changes that result in a global model when aromatics, terpenes, and ethene are included. The model is IMPACT, a global 3-dimensional chemistry/transport model developed at Lawrence Livermore National Laboratories [{\it Rotman et al.}, 2004], with a modified numerical solution for photochemistry. The model has been exercised under the the NASA Global Modeling Initiative (GMI, http://gmi.gsfc.nasa.gov) using the photochemical representation from {\it Fiore and Jacob} [2003]. This has been compared to a modified calculation using extended photochemistry. The extensions include three primary aromatic species and two terpenes, along with various secondary reaction products. Isoprene nitrates are assumed to react with OH to produce NO$_{2}$ and secondary organics rather than decompose into HNO$_{3}$ directly. Results show that O$_{3}$ increases by up to 20% in source regions and 10% over much of the northern hemisphere when the additional organic species are included. The change in O$_{3}$ varies seasonally. PAN also increases by 20% in much of the northern hemisphere. NO$_{x}$ decreases by 20% in source regions and increases in remote locations, reflecting increased transport of NO$_{x}$ away from source regions by organic nitrates. Bey, I., D. Jacob, R. Yantosca, J. Logan, B. Field, A. Fiore, Q. Li, H. Liu, L. Mickley, and M. Schultz (2001), Global modeling of tropospheric chemistry with assimilated meteorology: Model description and evaluation, {\it J. Geophys. Res.}, {\it 106}, 23,073-23,096. Fiore, A., and D. J. Jacob (2003), {\it The GEOS-CHEM chemical mechanism version 5-07-8}, Harvard University, Cambridge, MA, USA. Rotman, D. A., et al. (2004), IMPACT, the LLNL 3-D global atmospheric chemical transport model for the combined troposphere and stratosphere: Model description and analysis of ozone and other trace gases, {\it J. Geophys. Res.}, {\it 109}, D04303, doi:10.1029/2002JD003155.
DE: 1610 Atmosphere (0315, 0325)
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting