DPS 2001 meeting, November 2001
Session 34. Mars Atmosphere II: Clouds and Dust
Oral, Chairs: M. Wolff, A. Colaprete, Thursday, November 29, 2001, 4:40-6:10pm, Regency E

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[34.09] The Infrared Signature of Martian Polar Clouds

P.G. Ford, G.H. Pettengill (MIT)

CO2 clouds in the Martian polar night have been monitored by the Mars Global Surveyor (MGS) Laser Altimeter experiment (MOLA) and used to derive a catalog of cloud locations and morphologies that spans the period from March 1998 to July 2001. For much of that time, the MGS Thermal Emission Spectrometer experiment (TES) viewed Mars from the same nadir direction as MOLA at wavelengths between 5.8 and 67\mum. Following the method first adopted by Kieffer et al., polar TES measurements have been interpolated to 15, 18, and 25\mum wavelengths, representing emission dominated, respectively, by an atmospheric region at about 20±5 km altitude; by the lowest scale height above the Martian surface; and by the surface itself. The MOLA cloud catalog has been combined with TES data to create polar maps of emission temperature when MOLA clouds were not observed, at intervals of 10\circ in Ls, and at each of the three chosen TES wavelengths. The cloud catalog was used again to determine emission temperatures at those times when MOLA and, by inference, TES, were observing CO2 clouds. The average temperature difference between the times when clouds were present and absent is significant at 18 and 25\mum, but not noticeable at 15\mum.

The author(s) of this abstract have provided an email address for comments about the abstract: pgf@space.mit.edu

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