Journal
NATURE
Volume 459, Issue 7247, Pages 678-682Publisher
NATURE PUBLISHING GROUP
DOI: 10.1038/nature08014
Keywords
-
Categories
Funding
- CNRS
- CEA
- CNES French
- Universities of Paris Diderot and Nantes
Ask authors/readers for more resources
Clouds on Titan result from the condensation of methane and ethane and, as on other planets, are primarily structured by circulation of the atmosphere(1-4). At present, cloud activity mainly occurs in the southern (summer) hemisphere, arising near the pole(5-12) and at mid-latitudes(7,8,13-15) from cumulus updrafts triggered by surface heating and/or local methane sources, and at the north (winter) pole(16,17), resulting from the subsidence and condensation of ethane-rich air into the colder troposphere. General circulation models(1-3) predict that this distribution should change with the seasons on a 15-year timescale, and that clouds should develop under certain circumstances at temperate latitudes (similar to 40 degrees) in the winter hemisphere(2). The models, however, have hitherto been poorly constrained and their long-term predictions have not yet been observationally verified. Here we report that the global spatial cloud coverage on Titan is in general agreement with the models, confirming that cloud activity is mainly controlled by the global circulation. The non-detection of clouds at latitude similar to 40 degrees N and the persistence of the southern clouds while the southern summer is ending are, however, both contrary to predictions. This suggests that Titan's equator-to-pole thermal contrast is overestimated in the models and that its atmosphere responds to the seasonal forcing with a greater inertia than expected.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available