HR: 1340h
AN: A23A-0769    [Abstracts]
TI: Ozone-CO relationships in plumes carrying North American pollution and boreal biomass burning emissions through the central North Atlantic lower free troposphere
AU: * Honrath, R E
EM: reh@mtu.edu
AF: Dept. of Civil and Environmental Engineering, Michigan Technological University 1400 Townsend Drive, Houghton, MI 49931-1295 United States
AU: Owen, R C
EM: rcowen@mtu.edu
AF: Dept. of Civil and Environmental Engineering, Michigan Technological University 1400 Townsend Drive, Houghton, MI 49931-1295 United States
AU: Val Mart\'{\i}n, M
EM: mvalmart@mtu.edu
AF: Dept. of Civil and Environmental Engineering, Michigan Technological University 1400 Townsend Drive, Houghton, MI 49931-1295 United States
AU: Reid, J S
EM: reidj@nrlmry.navy.mil
AF: Aerosol and Radiation Modeling Section, Marine Meteorology Division, Naval Research Laboratory, 7 Grace Hopper Ave., Stop 2, Monterey, CA 93943-5502 United States
AU: Lapina, K
EM: klapina@mtu.edu
AF: Dept. of Civil and Environmental Engineering, Michigan Technological University 1400 Townsend Drive, Houghton, MI 49931-1295 United States
AU: Kleissl, J P
EM: kleissl@mtu.edu
AF: Dept. of Civil and Environmental Engineering, Michigan Technological University 1400 Townsend Drive, Houghton, MI 49931-1295 United States
AU: Fialho, P
EM: paulo.fialho@angra.uac.pt
AF: Departamento de Ci^encias Agr'arias, Universidade dos Ac,ores, Angra do Heroismo, P-9701-851 Portugal
AB: North American anthropogenic activities and biomass burning are both significant sources of nitrogen oxides emissions. Recent studies have indicated changes in the NO$_x$\ to CO emission ratio in U.S. urban regions, and amplified response to global climate change in boreal regions is expected to result (and may already have resulted) in increased frequency of large boreal fires. The PICO-NARE mountaintop (2.2~km altitude) station in the Azores Islands is well situated to probe the overall impact of both processes on lower tropospheric O$_3$\ levels. Measurements made there during the summers of 2001--2003 have been analyzed to assess these impacts. The relationship between CO and O$_3$\ in North American pollution outflow was found to be significantly steeper than expected, with a slope ($d[{\rm O}_3]/d[{\rm CO}]$) averaging 1.0 ppbv/ppbv, implying significantly more ozone formation per unit CO emissions than observed in prior measurements over eastern North America and in the nearby downwind region. Potential reasons for this difference, including changes in eastern North American emissions of ozone precursors, airmass history, and NO$_{x,y}$\ export, will be discussed. In contrast to the moderate CO enhancements in North American outflow, we find that boreal fires in Siberia and North America result in the highest CO levels observed, produce ozone enhancements comparable to those in North American pollution outflow, and play a major role in interannual variability of CO. It has been suggested that the magnitude of boreal fires may be increasing as a result of changing boreal climate; these findings imply that such an increase could significantly impact hemispheric scale ozone, CO, and nitrogen oxides levels.
UR: http://www.cee.mtu.edu/~reh/pico
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting