HR: 17:50h
AN: P44A-08    [Abstracts]
TI: Wind-induced Seasonal Angular Momentum Exchange at Titan's Surface and its Influence on Titan's Length-of-day
AU: * Tokano, T
EM: tokano@geo.uni-koeln.de
AF: Institut für Geophysik und Meteorologie, Universität zu Köln, Albertus-Magnus-Platz, Köln, 50923 Germany
AU: Neubauer, F M
EM: neubauer@geo.uni-koeln.de
AF: Institut für Geophysik und Meteorologie, Universität zu Köln, Albertus-Magnus-Platz, Köln, 50923 Germany
AB: Titan's substantial obliquity and the global extent of the Hadley circulation give rise to a seasonal variation in the mean zonal wind speed and direction in the geostrophic lower troposphere. Consequently, a substantial amount of angular momentum is exchanged between the surface and atmosphere. Titan's rotational rate is more sensitive to atmospherically induced seasonal variation than the Earth's rotational rate because of Titan's slow rotational rate and dense atmosphere. The seasonal wind-induced length-of-day (LOD) variation of Titan calculated using the global wind profile predicted by a Titan general circulation model (GCM) amounts to 30 s in the absence of a deep subsurface ocean or 390 s in the presence of a deep ocean. This effect should give rise to longitudinal offsets of surface landmarks of the order of 100 km compared to predicted positions based on a constant rotation rate, and may be detectable by Cassini imaging.
DE: 5405 Atmospheres (0343, 1060)
DE: 5445 Meteorology (3346)
DE: 5450 Orbital and rotational dynamics (1221)
DE: 6281 Titan
SC: Planetary Sciences [P]
MN: Fall Meeting 2005