Date:
Location:
Speaker: Associate Professor Jonathan L. Mitchell from UCLA
Title: "Titan’s climate, and three questions about its methane cycle"
Abstract:
I will summarize key characteristics of the climate of Titan, Saturn’s largest moon, and then focus on answering three questions related to Titan’s methane cycle, which operates much like Earth’s water cycle. (1) Methane is cold-trapped to high latitudes, and more is present in the northern than in the southern hemisphere. Given the hemispheric symmetry of annual-mean insolation, what causes this hemispheric asymmetry? (2) Observations of Titan’s surface reveal the presence of alluvial fans, erosional features that are typically the result of intense precipitation. However, the weak solar driving of Titan’s climate produces very weak mean precipitation. How then do the alluvial fans form? (3) The seasonal distribution of methane clouds, observed surface methane distribution, and the co-location of the most intense precipitation and observed alluvial fans all require special “wetlands” surface boundary conditions, where methane is removed from (infiltrated into) the low-latitude surface and is held constant at high latitudes. What does this imply about Titan’s actual surface hydrology? relevant paper 1, 2