HR: 11:35h
AN: A22C-06    [Abstracts]
TI: Measurements of Short Chain (C$_{1}$-C$_{5}$) Alkyl Mononitrates and Related Compounds in North GRIP Firn air.
AU: * Worton, D R
EM: d.worton@uea.ac.uk
AF: University of East Anglia, School of Environmental Sciences, University of East Anglia., Norwich, NR4 7TJ United Kingdom
AU: Sturges, W T
AF: University of East Anglia, School of Environmental Sciences, University of East Anglia., Norwich, NR4 7TJ United Kingdom
AU: Schwander, J
AF: University of Bern, University of Bern, Physics Institute, Climate and Environmental Physics, Sidlerstrasse 5, Bern, CH-3012 Switzerland
AU: Mulvaney, R
AF: British Antarctic Survey, British Antarctic Survey High Cross, Madingley Road, Cambridge, CB3 0ET United Kingdom
AU: Chappellaz, J
AF: CNRS-LGGE, Laboratoire de Glaciologie et G‚ophysique de l'Environnement, 54 rue MoliŠre, Saint Martin d'HŠres, 38402 France
AU: Barnola, J
AF: CNRS-LGGE, Laboratoire de Glaciologie et G‚ophysique de l'Environnement, 54 rue MoliŠre, Saint Martin d'HŠres, 38402 France
AU: Atlas, E
AF: University of Miami, Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami, Coral Gables, Florida, 33124 United States
AB: The paleoclimatic history of tropospheric ozone and nitrogen oxides are not well known and cannot be measured in polar firn air. However, alkyl nitrates can be used as tracers of tropospheric ozone and nitrogen oxide (NO$_{x}$) levels as they are formed in a minor channel during the oxidation of NO to NO$_{2}$ by peroxy radicals. Ozone plays a critical role in the atmosphere, and is present in the troposphere through transport from the stratosphere and as a result of in situ photochemistry involving the oxides of nitrogen (NO and NO$_{2}$). It is important for both atmospheric photochemistry and the global radiation balance through its roles as a precursor for the hydroxyl radical and as a strong infrared absorber. The anthropogenic perturbation of these species is critical to understanding contemporary changes occurring within the climate system. We present short chain alkyl mononitrate (C$_{1}$-C$_{5}$) measurements from firn air recovered from North GRIP ($75.1\deg$N, $42.4\deg$W) in central Greenland and compare to previous measurements made at two Antarctic sites, Dome Concordia ($75.1\deg$S, $123.4\deg$E) and Dronning Maud Land ($75.0\deg$S, $65.0\deg$E). The difference between the two hemispheres is distinct and pronounced with the northern hemisphere showing the greatest variations. In the northern hemisphere, the butyl and pentyl nitrates (C$_{4}$-C$_{5}$) show interesting reconstructed paleoclimatic trends that illustrate steep growth from the beginning of the last century before levelling off in more recent times. We consider the implications of this data for the composition and photochemistry of the troposphere over the last century.
DE: 1704 Atmospheric sciences
DE: 1610 Atmosphere (0315, 0325)
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting