HR: 0830h
AN: P21D-05    [Abstracts]
TI: Photochemistry of the Martian Atmosphere: Global Model and Seasonal, Latitudinal, and Diurnal Variations
AU: * Krasnopolsky, V A
EM: vkrasn@verizon.net
AF: Department of Physics, Catholic University of America, 620 Michigan Avenue, N.E., Washington, DC 20064 United States
AB: Three types of models have been developed to study Mars' photochemistry. A steady-state model for global-mean conditions is the only way to calculate abundances of the long living species (H₂, O₂, and CO) and therefore to validate a chosen photochemistry. A steady-state model for local conditions adopts the known abundances of H₂, O₂, and CO and the photochemistry from the global-mean model to simulate the measured abundances of O₃, O₂(¹Δ), and H₂O₂ and their variations with local conditions for a diurnal-mean insolation. A time-dependent model for local conditions is for the same purpose but accounts for the local-time variability. The local models were calculated at the conditions of the O₃ (Espenak et al. 1991, Clancy et al. 1999), O₂(¹Δ) (Krasnopolsky 2003), and H₂O₂ (Clancy et al. 2004, Encrenaz et al. 2004) observations. Input data for the models (temperature profiles, H₂O abundances, and dust opacities) are taken from the MGS/TES observations (Smith 2004), simultaneous or made at similar conditions. Comparison of results of the models with the observations favors an effective heterogeneous sink of odd hydrogen on the surface of water ice particles in the clouds and hazes on Mars. This sink reduces the strong anticorrelation between water vapor and ozone which follows from the pure gas-phase models. Results of the modeling and their implications will be discussed.
DE: 5405 Atmospheres--composition and chemistry
DE: 5409 Atmospheres--structure and dynamics
DE: 5410 Composition
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2005 Joint Assembly