Monday 17 Feb 2014: From Earth to Titan and Beyond (MON 10:30am)

Prof Jonathan Mitchell - University of California, Los Angeles

Physics, 4th floor 10:30-11:30

Saturn’s moon Titan is perhaps the most Earth­like body in the Solar System, having a thick nitrogen atmosphere, a substantial greenhouse effect, and an active weather cycle that shapes its surface. But that’s where the similarities end. I will review essential observations that distinguish Earth’s and Titan’s atmospheres. Then using a hierarchy of atmospheric circulation models with varying complexity, I will identify mechanisms giving rise to two phenomena that are unique to Titan: (1) A seasonal monsoon­like circulation that reverses the direction of Titan’s entire tropospheric overturning and (2) superrotating zonal winds that make its atmosphere spin faster than its surface. Earth and Titan form end­members of our simulated atmospheres, and the result is a kind of ‘phase diagram’ for emergence of the phenomena under investigation. I will end with a discussion of our plans to extend the analysis to Venus and 'mini­Neptune' exoplanets.

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