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[37.15] Seasonal Mapping of Ozone in the Middle Atmosphere of Mars

A. Farrell, T. Dunne, R. Novak, Y. Cabral (Iona College), M.J. Mumma (NASA's GSFC), B. Bonev (University of Toledo - NASA's GSFC)

New observations of Mars' atmosphere were taken at NASA's IRTF on Jan. 11-15, 2004 (L_s ~ 333 degrees). Photolysis of ozone in Mars' atmosphere by UV sunlight (Hartley bands) produces a singlet-Delta state of O₂; emissions from this state (1.27 \mum band) are used as a tracer for atmospheric ozone above ~ 20 km since the singlet-Delta state is quench by carbon dioxide at lower altitudes[1]. We used CSHELL (0.5 arc-sec slit width, resolving power ~ 40000) on the IRTF for these observations. The slit was oriented both north-south and east-west on Mars. For both orientations, no detectible emission from the singlet Delta state of O₂ was observed. This is similar to results obtained on Jan 8-12, 2002 (L_s ~ 306 degrees), but is drastically different from measurements of March 18-24, 2003 (L_s ~ 155 degrees) when a strong singlet-Delta emission was observed in the southern hemisphere of Mars; a 2-D map from this date will be presented along with maps taken at different seasonal dates. This is part of a larger project that began in 1997. We are currently studying the ratio between HDO and H₂O, and the isotopic forms of other gases such as CO₂ in Mars’ atmosphere.

This project was partially funded through grant from NASA’s Planetary Astronomy Program (RTOP 344-32-51-96 to M. J. Mumma) and NSF RUI Program (AST-0205397 to R. E. Novak).

[1] Novak, R. E. et al. (2002), Icarus 158, 14-23.

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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.