Dix Planetary Science Seminar

Titan harbors a rich hydroclimate with geomorphological evidence of surface runoff, subsurface reservoirs, and sediment transport by intense rainstorms. Regional patterns in these surface features suggest corresponding regional climatic influences, namely in the form of precipitation from the atmosphere. A model coupling the atmosphere to a surface hydrology scheme is therefore required to fully explore Titan's surface-atmosphere connections. Previous general circulation models (GCMs) of Titan have successfully reproduced Titan's climate but have done so in physically inconsistent ways and neglected basic representations of surface hydrology. I will present a new Titan GCM that includes simple parameterizations of surface and subsurface flow, infiltration, and groundwater evaporation, and discuss the resulting large-scale climate dynamics. The model promotes poleward methane transport by surface/subsurface flows into saturated high-latitude lowlands and equatorward methane transport by the atmosphere into unsaturated low-latitude highlands. Infiltration into unsaturated soils then dries the lower latitudes. The model therefore reproduces Titan's observed equatorial desert and polar wetlands regions but within a more physically consistent framework than past GCMs.