Atmospheric dynamics of terrestrial exoplanets over a wide range of orbital and atmospheric parameters

The recent discoveries of terrestrial exoplanets and super Earths extending over a broad range of orbital and physical parameters suggests that these planets will span a wide range of climatic regimes.

Characterization of the atmospheres of warm super Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone---including transitions to Snowball-like states and runaway-greenhouse feedbacks---depend on the equator-to-pole temperature differences, pattern of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model (GCM) including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets.

We show how the planetary rotation rate, planetary mass, surface gravity, heat flux from a parent star, optical thickness and atmospheric mass affect the atmospheric circulation and temperature distribution on such planets. Our simulations demonstrate that equator-to-pole temperature differences, meridional heat transport rates, structure and strength of the winds, and the hydrological cycle vary strongly with these parameters, implying that the sensitivity of the planet to global climate feedbacks will depend significantly on the atmospheric circulation. We elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet stream, Hadley and Ferrel cells and latitudinal temperature differences. Finally, we discuss the implications for understanding how the atmospheric circulation influences the global climate.

Yohai Kaspi, Adam P. Showman (Submitted on 23 Jul 2014)

Comments: 18 pages, 20 figures, submitted to ApJ

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Cite as: arXiv:1407.6349 [astro-ph.EP] (or arXiv:1407.6349v1 [astro-ph.EP] for this version)

Submission history From: Yohai Kaspi [v1] Wed, 23 Jul 2014 19:58:14 GMT (4133kb,D)

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