GCM simulations of Titan's middle and lower atmosphere and comparison to observations

Abstract

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.

Accepted for publication in Icarus

References in corpus (2)

• Global circulation as the main source of cloud activity on Titan
• Simulations of Titan's paleoclimate

Cited by in corpus (16)

• The Composition and Chemistry of Titan's Atmosphere
• The near-surface methane humidity on Titan
• The Fundamental Connections Between the Solar System and Exoplanetary Science
• Possible Atmospheric Diversity of Low Mass Exoplanets, some Central Aspects
• An axisymmetric limit for the width of the Hadley cell on planets with large obliquity and long seasonality
• Ground-based HCN submillimetre measurements in Titan's atmosphere: an intercomparison with Herschel observations
• The Atmosphere of Titan in Late Northern Summer from JWST and Keck Observations
• The Trouble with Water: Condensation, Circulation and Climate
• The impact of lake shape and size on lake breezes and air-lake exchanges on Titan
• Photochemical Haze Formation on Titan and Uranus: A Comparative Review
• Reducing Surface Wetness Leads to Tropical Hydrological Cycle Regime Transition
• Measurements of Titan's Stratospheric Winds during the 2009 Equinox with the eSMA
• Rapid Automated Mapping of Clouds on Titan With Instance Segmentation
• Open Questions and Future Directions in Titan Science
• Science goals and new mission concepts for future exploration of Titan's atmosphere geology and habitability: Titan POlar Scout/orbitEr and In situ lake lander and DrONe explorer (POSEIDON)
• Superrotation of Titan's stratosphere driven by the radiative heating of the haze layer