10 Years of Cloud Cover Monitoring on Titan with Vims on Board Cassini
Tuesday, 16 December 2014
We report on the monitoring of cloud activity in Titan’s atmosphere over a period spanning from early winter to mid-spring. Clouds on Titan have been observed by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft since its insertion into Saturn’s orbit. A semi-automated method is used to detect cloud events in each VIMS cube acquired since July 2004 and statistics are drawn on the location of the clouds and their evolution. It is shown that the cloud activity has decreased at both pole approaching the equinox, while clouds at southern mid-latitudes are still very active. Close to the equinox, rare but intense cloud activity has also been detected in the equatorial area. After the equinox, the cloud activity has almost completely disappeared, except for rare and small cloud patches at northern high latitudes. Those long-term observations are compared with predictions of Global Circulation Models (GCMs) in order not only to better constrain the models, but also to better understand the processes which drive Titan’s weather and how they interact with Titan's surface.