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
Saturnís moon Titan is perhaps the most Earth≠like body in the Solar System, having a thick nitrogen atmosphere, a substantial greenhouse effect, and an active weather cycle that shapes its surface. But thatís where the similarities end. I will review essential observations that distinguish Earthís and Titanís 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 monsoon≠like circulation that reverses the direction of Titanís entire tropospheric overturning and (2) superrotating zonal winds that make its atmosphere spin faster than its surface. Earth and Titan form end≠members of our simulated atmospheres, and the result is a kind of Ďphase diagramí for emergence of the phenomena under investigation. I will end with a discussion of our plans to extend the analysis to Venus and 'mini≠Neptune' exoplanets.