DPS 2001 meeting, November 2001
Session 44. Mars Atmosphere III: Aeronomy
Oral, Chair: M. Mendillo, Friday, November 30, 2001, 11:30am-12:30pm, Regency GH

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[44.03] Measurements of Non-Thermal Infrared Emission Lines of Carbon Dioxide in the Mars Upper Atmosphere

T. A. Livengood (Challenger Center), T. Kostiuk, W. C. Maguire (NASA GSFC), J. D. Delgado (U of MD, College Park), J. C. Pearl, M. D. Smith, D. Deming, F. Espenak (NASA GSFC), T. Hewagama (U of MD, College Park)

Infrared transitions of normal-isotope carbon dioxide were observed in emission from the upper atmosphere of Mars and in absorption in the lower atmosphere with a spectral resolving power of \lambda /\Delta \lambda = 5 \times 106 using the new Heterodyne Instrument for Planetary Winds and Composition (HIPWAC) at the NASA Infrared Telescope Facility on 3--5 August 2001 (UT). Spectra were obtained from positions along or near to the 2PM meridian ground track of the Mars Global Surveyor spacecraft in order to correlate the observed emission lines with spatial mapping of the vertical and meridional extent of emission observed at low spectral resolution in limb-scanning observations by the MGS Thermal Emission Spectrometer (TES) instrument. The measured emission lineshapes, at rest frequencies of 951.1923 cm-1 (10.513 \mum), 954.5451 cm-1 (10.476 \mum), and at 936.8037 cm-1 (10.675 \mum), provide a constraint on the kinetic temperature of the source region and an upper limit on the pressure in the source region due to the negligible pressure-broadening observed. Pressure-broadened absorption of the 951.1923 cm -1 line observed at disc center serendipitously provides a constraint on the upper altitude reached in the observed region by the global dust storm in progress at the time, due to variable depth in the CO2 absorption feature.

The author(s) of this abstract have provided an email address for comments about the abstract: timothy.a.livengood@gsfc.nasa.gov

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