HR: 1340h
AN: SA23A-1132    [Abstracts]
TI: N2O production during high energy auroral precipitation
AU: * McConnell, J C
EM: jcmcc@yorku.ca
AF: Centre for Earth and Space Science, York University 4700 Keele Street, Toronto, ON M3J 1P3, Canada
AU: Semeniuk, K
EM: kirill@nimbus.yorku.ca
AF: Centre for Earth and Space Science, York University 4700 Keele Street, Toronto, ON M3J 1P3, Canada
AU: Bernath, P
EM: pfb500@york.ac.uk
AF: University of York, Heslington, York, YO10 5DD, United Kingdom
AU: Jin, J
EM: jin@nimbus.yorku.ca
AF: Centre for Earth and Space Science, York University 4700 Keele Street, Toronto, ON M3J 1P3, Canada
AU: Fu, C
EM: Chao.Fu@space.gc.ca
AF: Canadian Space Agency, 6767, Route de l'Aéroport, St-Hubert, QC J3Y 8Y9, Canada
AU: Jaroz, J
EM: jjarosz@yorku.ca
AF: Centre for Earth and Space Science, York University 4700 Keele Street, Toronto, ON M3J 1P3, Canada
AB: The ACE instrument on SCISAT-I observed very high values of NOx in the lower polar mesosphere in February of 2004. It also measured unusually high mesospheric values of N2O as adduced by both absolute amount and by comparison with simultaneously measured CH4 data. GOMOS data for the same period have revealed high polar NO2 values. Anomalous N2O values in the mesosphere have also been seen by ACE in other years. We suggest that the excess N2O is produced by the reaction of N with NO2. Atomic N is critical to the production and questions arise as to whether N produced by solar radiation of NO is adequate to drive the process is there are high mixing ratios of NO. Thus we have used the CMAM chemistry climate model to examine whether the N2O production is driven by NOx transport from above and photolysis or by in-situ production of N and NO by high energy electron ionization. Our results suggest that N produced by auroral ionization is essential for the production of N2O and, given the short lifetime of N, that N2O is produced locally where NO2 is present below around 80 km. The ionization rate is inferred from observations of electron fluxes and energies by the MEPED instruments on NOAA polar orbiting environmental satellites.
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
SC: SPA-Aeronomy [SA]
MN: 2007 Fall Meeting