HR: 08:30h
AN: A31E-02    [Abstracts]
TI: Are Emissions of Restricted Halocarbons in the USA and Canada Still Globally Significant?
AU: * Hurst, D F
EM: Dale.Hurst@noaa.gov
AF: CIRES, University of Colorado, Campus Box 216, Boulder, CO 80309 United States
AU: Romashkin, P A
AF: CIRES, University of Colorado, Campus Box 216, Boulder, CO 80309 United States
AU: Hall, B D
AF: NOAA/CMDL, 325 Broadway R/CMDL1, Boulder, CO 80305 United States
AU: Elkins, J W
AF: NOAA/CMDL, 325 Broadway R/CMDL1, Boulder, CO 80305 United States
AU: Lin, J C
AF: Harvard University, 20 Oxford Street, Cambridge, MA 02138 United States
AU: Gerbig, C
AF: Harvard University, 20 Oxford Street, Cambridge, MA 02138 United States
AU: Daube, B C
AF: Harvard University, 20 Oxford Street, Cambridge, MA 02138 United States
AU: Wofsy, S C
AF: Harvard University, 20 Oxford Street, Cambridge, MA 02138 United States
AB: The global manufacture of halocarbons regulated by the Montreal Protocol has dropped substantially in response to the January 1, 1996, production phase-out deadline (1994 for halons) for developed (Article 5) countries like the United States and Canada. Contemporary emissions of these ozone-depleting substances (ODS) emanate from ongoing production in developing countries and releases of banked halocarbons world-wide. ODS emissions in developing nations can be appraised from reported production figures, but not so for developed nations where recent manufacture is negligible. Emissions in the United States and Canada are increasingly difficult to estimate because of limited information about bank sizes and release rates in the post-production era. In addition, regional- or national-scale emission estimates should no longer be derived wholly from localized measurements because of the potentially patchy spatial distributions of modern emissions. We estimate ODS emissions in the USA and Canada from $>$1000 simultaneous, in situ measurements each of CO and six restricted halocarbons (CFC-11, CFC-12, CFC-113, methyl chloroform, carbon tetrachloride, and halon-1211) in and above the planetary boundary layer during the 2003 CO$_{2}$ Budget and Regional Airborne - North America (COBRA-NA 2003) study. The data obtained during 87 flight hours are geographically extensive ($>$30,000 km) including two 11,000 km flight circuits across both countries. More than 50 pollution "events" with statistically significant ODS:CO emission ratios were sampled, and for each event we have determined a flux footprint using the Stochastic Time-Inverted Lagrangian Transport (STILT) model. The model also calculates footprint-weighted average population densities and CO fluxes which we convert to footprint-weighted average ODS fluxes using the measured ODS:CO emission ratios. Statistically robust relationships between footprint-averaged ODS fluxes and population densities for several ODS indicate that population-based extrapolations of these relationships to national levels are warranted. Emission estimates for the USA and Canada in 2003 will be presented and compared to the magnitudes of global emissions.
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting