HR: 1340h
AN: SA13A-1123    [Abstracts]
TI: Oxidant Enhancement in Martian Dust Devils and Storms II
AU: * Atreya, S K
EM: atreya@umich.edu
AF: Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143 United States
AU: Wong, A
EM: aswong@umich.edu
AF: Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143 United States
AU: Renno, N O
EM: nrenno@umich.edu
AF: Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143 United States
AU: Farrell, W M
EM: farrell@faltraz.gsfc.nasa.gov
AF: NASA, Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Delory, G T
EM: gdelory@ssl.berkeley.edu
AF: University of California, Space Sciences Laboratory MS 7450, Berkeley, CA 94720 United States
AU: Sentman, D
EM: dsentman@gi.alaska.edu
AF: University of Alaska, University of Alaska, Fairbank, AK 99775 United States
AU: Cummer, S
EM: cummer@ee.duke.edu
AF: Duke University, Campus Box 90291, Durham, NC 27708 United States
AU: Marshall, J
EM: jmarshall@seti.org
AF: SETI Institute, 515 North Whisman Road, Mountain View, CA 94043 United States
AU: Rafkin, S
EM: srafkin@boulder.swri.edu
AF: Southwest Research Institute, Department of Space Studies, Boulder, CO 80302 United States
AU: Catling, D
EM: davidc@atmos.washington.edu
AF: University of Washington, Box 351640, Seattle, WA 98195 United States
AB: The failure of the Viking Life Sciences Experiments to find organics on Mars has been suggested as being due to the presence of oxidants. In particular, hydrogen peroxide (H$_2$O$_2$) has been proposed as the most likely oxidizer of the surface of Mars. H$_2$O$_2$ was detected in 2003, and the measured mixing ratio, 20-30 ppb, agrees well with global photochemical models. However, this abundance of H$_2$O$_2$ is perhaps not large enough to account for the above Viking result. In this presentation, we will discuss a new mechanism that can produce substantially greater abundance of H$_2$O$_2$. Delory et al. (see previous companion presentation) have shown that triboelectric fields in martian dust devils and storms may be near 20 kV/m, and have determined the production rates of OH and O- from dissociation of H$_2$O and CO$_2$ via electric field driven electrons. Using a chemical model, we calculate that the abundance of H$_2$O$_2$ due to electrochemistry in dust devils and storms greatly exceeds that produced photochemically. Since the aeolian processes must have been prevalent throughout the martian geologic history, this effect of H$_2$O$_2$ enhancement, together with the large UV radiation reaching the martian surface, implies that the martian surface and near-surface environment are unlikely to be hospitable to life.
DE: 5405 Atmospheres--composition and chemistry
DE: 6225 Mars
DE: 3346 Planetary meteorology (5445, 5739)
DE: 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707)
DE: 0614 Biological effects
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting