Atmospheric Circulation of Terrestrial Exoplanets

Abstract

The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical and dynamical conditions, only a small fraction of which have yet been explored in detail. Our approach is to lay out the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined--and show how they can provide a foundation for understanding the atmospheric behavior of these worlds. We first survey basic atmospheric dynamics, including the role of geostrophy, baroclinic instabilities, and jets in the strongly rotating regime (the "extratropics") and the role of the Hadley circulation, wave adjustment of the thermal structure, and the tendency toward equatorial superrotation in the slowly rotating regime (the "tropics"). We then survey key elements of the hydrological cycle, including the factors that control precipitation, humidity, and cloudiness. Next, we summarize key mechanisms by which the circulation affects the global-mean climate, and hence planetary habitability. In particular, we discuss the runaway greenhouse, transitions to snowball states, atmospheric collapse, and the links between atmospheric circulation and CO2 weathering rates. We finish by summarizing the key questions and challenges for this emerging field in the future.

Invited review, in press for the Arizona Space Science Series book "Comparative Climatology of Terrestrial Planets" (S. Mackwell, M. Bullock, and J. Harder, editors). 56 pages, 26 figures

Cited by in corpus (17)

• Exoplanetary Atmospheres - Chemistry, Formation Conditions, and Habitability
• Exoplanet Biosignatures: A Framework for Their Assessment
• Atmospheric Dynamics of Hot Exoplanets
• Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature Differences. II. Comparison with Observations
• Possible climates on terrestrial exoplanets
• The Effect of Orbital Configuration on the Possible Climates and Habitability of Kepler-62f
• Towards multi-dimensional analysis of transmission spectroscopy. Part II: Day-night induced biases in retrievals from hot to ultra-hot Jupiters
• Ice Giant Circulation Patterns: Implications for Atmospheric Probes
• Terminator Habitability: the Case for Limited Water Availability on M-dwarf Planets
• The Effect of Land Albedo on the Climate of Land-Dominated Planets in the TRAPPIST-1 System
• Axisymmetric constraints on cross-equatorial Hadley cell extent
• 3-D climate simulations for the detectability of Proxima Centauri b
• Sensitivity of the Atmospheric Water Cycle within the Habitable Zone of a Tidally-Locked, Earth-like Exoplanet
• Hurricanes on tidally locked terrestrial planets: Fixed surface temperature experiments
• The dependence of global super-rotation on planetary rotation rate
• Meta-modelling the climate of dry tide locked rocky planets
• Lightning activity on a tidally locked terrestrial exoplanet in storm-resolving simulations for a range of surface pressures