HR: 08:10h
AN: AE21A-02 INVITED     [Abstracts]
TI: Production of Nitric Oxide in Continental Thunderstorms
AU: * Ridley, B
EM: ridley@ucar.edu
AF: National Center for Atmospheric Research, PO Box 3000, Boulder, CO 80307 United States
AB: The global production of NO by thunderstorms is uncertain but is likely in the range of 2-20 Tg(N)/yr. Current global Chemistry-Transport models would imply a narrower range of 2-7 Tg(N)/yr or about 10-20 percent of the current annual emissions from fossil fuel burning. Although a number of aircraft studies of continental thunderstorms have been made, they have not been able to really refine the global estimate. They have shown that large mixing ratios of NOx (NO + NO2) are found in the anvil outflow region of active storms due to lightning production and, depending on location, transport of NOx (and other reactive constituents) from near or within the boundary layer. Direct injection to high altitudes has unique chemical consequences compared to near-surface emissions because the lifetime of NOx is several days to a week. The chemical impact on, for example, ozone production or HOx radical partitioning can be much broader than the scale of the original thunderstorm. The aircraft programs combined with model analyses or interferometer observations have also shown that in some storms the NO production by intra-cloud flashes approaches the production by cloud-to-ground flashes. Here, observations of unexpectedly high mixing ratios of NO measured within Florida thunderstorm anvils during the NASA CRYSTAL-FACE study will be discussed and coarse estimates of the production per flash for storms of quite different size and electrical activity will be summarized. Some of the issues for possible future studies of the chemical impact of electrically active deep convection will also be considered.
DE: 3324 Lightning
DE: 3362 Stratosphere/troposphere interactions
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting