37th DPS Meeting, 4-9 September 2005
Session 24 Mars III
Oral, Tuesday, September 6, 2005, 2:00-3:50pm, Music Concert Hall

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[24.03] Structure of the Martian atmosphere in the polar regions: PFS and OMEGA data

L.V. Zasova (IKI - RAS, Moscow, Russia, IFSI - INAF, Rome, Italy), V. Formisano, D. Grassi (IFSI - INAF, Rome, Italy), N.I. Ignatiev (IKI - RAS, Moscow, Russia, IFSI - INAF, Rome, Italy), F. Altieri, G. Bellucci (IFSI - INAF, Rome, Italy), J.-P. Bibring (IAS, Orsay, France), M. Giuranna, A. Maturilli (IFSI - INAF, Rome, Italy)

Temperature retrieval is the main scientific goal for the longwavelength channel of the PFS on Mars Express. It covers a spectral range 300 - 1500 cm-1 with spectral resolution 1.8 cm-1 and allows to retrieve a vertical temperature profile from the surface up to 50-55 km altitude. Seasonal and spatial variations of temperature profiles in polar regions are discussed. The ``elevated" temperature inversion is found in N-polar region at Ls = 330-3420. Amplitude of thermal inversion reaches 20K in the polar hood and smoothes out above the CO2 polar cap, where position of temperature maximum corresponds to the higher altitudes not available for the observations with PFS. At latitudes exceeding 600 N the temperature becomes to be low enough for the CO2 to be condensate on the surface - the edge of the Northern seasonal CO2 polar cap. Temperature profiles, obtained from the PFS data at late winter show that the CO2 condensation in the atmosphere may occur at latitudes exceeding 700 N below 20 km altitude. The CO2 clouds may be observed even on the day side not far from the terminator. Simultaneous observations with OMEGA reveal the wave-like pattern where the condensation of the CO2 in the atmosphere follows from the PFS data. The wave-like features are clearly seen in the CO2 and H2O ice clouds absorptions (being anticorrelated), the O2 emission and the O3 distribution. The wave structure is observed in the latitude range from 70 degrees N up to terminator (80 degrees N). The crests of these waves are parallel to the terminator, and their wavelength changes from several tens km up to 100 - 150 km near terminator. We acknowledge the Russian Foundation of Basic Research for grant RFFI 04-02-16856 and IFSI-INAF for support to Russian CoIs.

The author(s) of this abstract have provided an email address for comments about the abstract: zasova@irn.iki.rssi.ru

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