  Simulation results are presented from a new general circulation model (GCM)
of Titan, the Titan Atmospheric Model (TAM), which couples the Flexible
Modeling System (FMS) spectral dynamical core to a suite of
external/sub-grid-scale physics. These include a new non-gray radiative
transfer module that takes advantage of recent data from Cassini-Huygens,
large-scale condensation and quasi-equilibrium moist convection schemes, a
surface model with "bucket" hydrology, and boundary layer turbulent diffusion.
The model produces a realistic temperature structure from the surface to the
lower mesosphere, including a stratopause, as well as satisfactory
superrotation. The latter is shown to depend on the dynamical core's ability to
build up angular momentum from surface torques. Simulated latitudinal
temperature contrasts are adequate, compared to observations, and polar
temperature anomalies agree with observations. In the lower atmosphere, the
insolation distribution is shown to strongly impact turbulent fluxes, and
surface heating is maximum at mid-latitudes. Surface liquids are unstable at
mid- and low-latitudes, and quickly migrate poleward. The simulated humidity
profile and distribution of surface temperatures, compared to observations,
corroborate the prevalence of dry conditions at low latitudes. Polar cloud
activity is well represented, though the observed mid-latitude clouds remain
somewhat puzzling, and some formation alternatives are suggested.

Earth and Planetary Astrophysics