HR: 0800h
AN: P31A-0185    [Abstracts]
TI: Mapping the temperature and composition of Saturn's stratosphere from Cassini/CIRS observations
AU: * Fouchet, T
EM: thierry.fouchet@obspm.fr
AF: Observatoire de Paris, 5 Place Jules Janssen, Meudon, 92195, France
AU: Guerlet, S
EM: sandrine.guerlet@obspm.fr
AF: Observatoire de Paris, 5 Place Jules Janssen, Meudon, 92195, France
AU: Strobel, D F
EM: strobel@jhu.edu
AF: Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, United States
AU: Simin-Miller, A A
EM: Amy.Simon@nasa.gov
AF: NASA/GSFC, Code 693, Greenbelt, MD 20771, United States
AU: Bézard, B
EM: bruno.bezard@obspm.fr
AF: Observatoire de Paris, 5 Place Jules Janssen, Meudon, 92195, France
AU: Flasar, M F
EM: f.m.flasar@nasa.gov
AF: NASA/GSFC, Code 693, Greenbelt, MD 20771, United States
AB: Using the limb observations provided by the Composite Infrared Spectrometer aboard the Cassini spacecraft, we obtained an unprecedended map of the temperature between 20~hPa to 0.003~hPa, and of the composition (ethane and acetylene) between 10~hPa and 0.01~hPa, with a vertical resolution of 1.5 times a scale height. The statospheric temperature structure and the derived thermal wind structure show the presence of an equatorial oscillation similar to the terrestrial QBO and jovian QQO. At extratropical latitudes, the temperature structure exhibits a smoother increase with altitude. However, in the upper stratosphere, the radiative cooling rates at mid-latitudes in northern and southern hemispheres does not balance with the local solar heating rates. This desiquilibrium can be explained by a meridional circulation from the southern to the northern hemisphere. The composition of the stratosphere, with enhancement of hydrocarbon abundance in the northern hemisphere at high altitudes constitutes another evidence for a meridional circulation.
DE: 5210 Planetary atmospheres, clouds, and hazes (0343)
DE: 5704 Atmospheres (0343, 1060)
DE: 5739 Meteorology (3346)
DE: 6275 Saturn
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting