HR: 0800h
AN: B41B-0117    [Abstracts]
TI: Interannual Variability of Global Biomass Burning Using Atmospheric Measurements of Carbon Monoxide and Hydrogen
AU: * Butenhoff, C
EM: christop@global.phy.pdx.edu
AF: Portland State University, Dept. of Physics PO Box 751 , Portland, OR 97232 United States
AU: Khalil, A
EM: aslamk@pdx.edu
AF: Portland State University, Dept. of Physics PO Box 751 , Portland, OR 97232 United States
AB: Biomass burning is a significant contributor to the global budgets of many environmentally important trace gases. Its sources are both natural and anthropogenic and any number of variables can affect its emissions over annual and decadal timescales. An important outstanding question in global change science is, have the emissions of biomass burning changed appreciably over recent years? We use a novel technique to address this question utilizing global atmospheric measurements of carbon monoxide (CO) and hydrogen (H2). These are both produced in large quantities by biomass burning, but are removed by different processes. We invert the measurements using a two-dimensional transport model to obtain a twenty-year time series of their respective sources. We find that these source histories are in good agreement with one another and share similar features and interannual variations. As the sinks for these gases are different, the agreement must reflect changes in a common source. If we restrict our analysis to the tropics where biomass burning is greatest, the main common sources of CO and H2 are oxidation from methane and non-methane hydrocarbons (NMHCs), and biomass burning. We argue that variability in the source time series most likely reflects changes in biomass burning, as we can account for the methane oxidation source, and the other source is dominated by natural NMHCs, which are not expected to vary significantly. We conclude that though the biomass burning record has large interannual variability, there is no evidence for a significant decadal trend. This work was supported in part by a grant from the Department of Energy (Grant DE-FG03-97ER62401) and the resources of the Andarz Co.
DE: 1610 Atmosphere (0315, 0325)
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere--composition and chemistry
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting