HR: 1340h
AN: A53B-1141    [Abstracts]
TI: NOx and HONO Emissions from Natural Snow Surfaces in a Temperature Controlled Laboratory
AU: * Beine, H
EM: harry108@caltech.edu
AF: Caltech, 1200 E. California Blvd, Pasadena, CA 91125,
AU: * Beine, H
EM: harry108@caltech.edu
AF: C.N.R. - IIA, Via Salaria Km 29,3, Monterotondo Scalo, RM 00016, Italy
AU: Amoroso, A
AF: C.N.R. - IIA, Via Salaria Km 29,3, Monterotondo Scalo, RM 00016, Italy
AU: Esposito, G
AF: C.N.R. - IIA, Via Salaria Km 29,3, Monterotondo Scalo, RM 00016, Italy
AU: Colussi, A J
AF: Caltech, 1200 E. California Blvd, Pasadena, CA 91125,
AU: Montagnoli, M
AF: C.N.R. - IIA, Via Salaria Km 29,3, Monterotondo Scalo, RM 00016, Italy
AU: Allegrini, I
AF: C.N.R. - IIA, Via Salaria Km 29,3, Monterotondo Scalo, RM 00016, Italy
AU: Hoffmann, M R
AF: Caltech, 1200 E. California Blvd, Pasadena, CA 91125,
AB: Photochemical production of NO_x and HONO from surface snow can significantly impact the NO_x, OH, and O₃ budgets in the overlying atmosphere. NO_x production is initiated by the solar photolysis of NO₃^- within or at the surface of snowpacks. HONO is deemed to be a secondary species whose formation likely involves H-atom transfer between NO₂ and natural humic substances. Climate and Global change can potentially affect the rate and efficiency of the NO₃^- (atm) -> NO₃^- (snow) -> NO_x/HONO (atm) cycle via altered solar UV radiation spectrum and/or fluxes, concentration of pollutants, temperature and snow cover. As part of the international multidisciplinary OASIS (Ocean-Atmosphere-Sea Ice-Snowpack) program, emission fluxes of NO, NO₂, and HONO from mid-latitude natural surface snow slabs were measured under controlled temperature, ozone mixing ratio and actinic flux conditions. Peak emission fluxes reached into the 0.5 to 1.5×10¹² [molecules cm^-2 sec^-1] range for the three species, or ~ 10³ times larger than those typically reported above Polar snowpacks. We present and analyze experimental results on the effects of temperature, actinic flux and the presence of humic acids on NO, NO₂, and HONO emissions.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0365 Troposphere: composition and chemistry
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0736 Snow (1827, 1863)
DE: 1610 Atmosphere (0315, 0325)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting