Dissipation of Titan's north polar cloud at northern spring equinox

Research areas:
Year:
2012
Authors:
Journal:
PLANETARY AND SPACE SCIENCE
Volume:
60
Number:
1
Pages:
86-92
Month:
January
ISSN:
0032-0633
Note:
Titan Through Time-A Workshop on Titans Formation, Evolution and Fate, MD, APR 06-08, 2010
Abstract:
Saturn's Moon Titan has a thick atmosphere with a meteorological cycle.
We report on the evolution of the giant cloud system covering its north
pole using observations acquired by the Visual and Infrared Mapping
Spectrometer onboard the Cassini spacecraft. A radiative transfer model
in spherical geometry shows that the clouds are found at an altitude
between 30 and 65 km. We also show that the polar cloud system vanished
progressively as Titan approached equinox in August 2009, revealing at
optical wavelengths the underlying sea known as Kraken Mare. This
decrease of activity suggests that the north-polar downwelling has begun
to shut off. Such a scenario is compared with the Titan global
circulation model of Rannou et al. (2006), which predicts a decrease of
cloud coverage in northern latitudes at the same period of time. (C)
2011 Elsevier Ltd. All rights reserved.