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| Titel |
Singular climatic activity at Equinox over Titan's dunefields as seen by CASSINI |
| VerfasserIn |
Sebastien Rodriguez, Stéphane Le Mouélic, Jason W. Barnes, Benjamin Charnay, Jasper F. Kok, Ralph D. Lorenz, Jani Radebaugh, Thomas Cornet, Olivier Bourgeois, Antoine Lucas, Pascal Rannou, Caitlin A. Griffith, Athena Coustenis, Thomas Appéré, Mathieu Hirtzig, Christophe Sotin, Jason M. Soderblom, Robert H. Brown, Jacob Bow, Graham Vixie |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250126855
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| Publikation (Nr.) |
 EGU/EGU2016-6641.pdf |
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| Zusammenfassung |
| Titan, the largest satellite of Saturn, is the only satellite in the solar system with a dense atmosphere. The close and continuous observations of Titan by the Cassini spacecraft, in orbit around Saturn since July 2004, bring us evidences that Titan troposphere and low stratosphere experience an exotic, but complete meteorological cycle similar to the Earth hydrological cycle, with hydrocarbons evaporation, condensation in clouds, and rainfall. Cassini monitoring campaigns also demonstrate that Titan’s cloud coverage and climate vary with latitude. Titan’s tropics, with globally weak meteorological activity and widespread dune fields, seem to be slightly more arid than the poles, where extensive and numerous liquid reservoirs and sustained cloud activity were discovered. Only a few tropo-spheric clouds have been observed at Titan’s tropics during the southern summer [2-4]. As equinox was approaching (in August 2009), they occurred more frequently and appeared to grow in strength and size [5-7].
We present here the observation of intense brightening at Titan’s tropics, very close to the equinox. These detec-tions were conducted with the Visual and Infrared Mapping Spectrometer [8] (VIMS) onboard Cassini. Figure 1 presents the VIMS color composite images of the three individual events detected so far, observed during the Titan’s flybys T56 (22 May 2009), T65 (13 January 2010) and T70 (21 June 2010). T56, T65 and T70 observations show an intense and transient brightening of large regions very close to the equator, which all appear spectrally and morphologically different from all previous observed surface features or atmospheric phenomena. These events share in particular a strong brightening at wavelengths greater than 2 µm (especially at 5 µm), making them spectrally distinct from the few large storms observed near the equator. We will discuss the possibility that these singular events may have occurred very close to the surface, having a very local origin. We will also discuss the possible implication of the equinoctial occurrence of such events for Titan’s tropical climatology and their probable link with particular geological features at Titan’s surface.
References: [1] Griffith et al. Astrophys. J. Letters 702, L105-L109, 2009. [2] Turtle et al., Geophys. Res. Lett. 36, CiteID L02204, 2009. [3] Rodriguez et al., Nature 459, 678-682, 2009. [4] Schaller et al., Nature 460, 873-875, 2009. [5] Turtle et al., Geophys. Res. Lett. 38, CiteID L03203, 2011. [6] Turtle et al., Science 331, 2011. [7] Rodri-guez et al., Icarus 216, 89-110, 2011. [8] Brown et al., Space Sci. Rev. 115, 111–168, 2004. |
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