Global modelling of the early Martian climate under a denser CO2 atmosphere: Water cycle and ice evolution

By R. Wordsworth, Francois Forget, Ehouarn Millour, James W. Head III, Jean-Baptiste Madeleine, B. Charnay. 2012

344 citations recorded by the source corpus.

Abstract We discuss 3D global simulations of the early martian climate that we have performed assuming a faint young Sun and denser CO 2 atmosphere. We include a self-consistent representation of the water cycle, with atmosphere–surface interactions, atmospheric transport, and the radiative effects of CO 2 and H 2 O gas and clouds taken into account. We find that for atmospheric pressures greater than a fraction of a bar, the adiabatic cooling effect causes temperatures in the southern highland valley network regions to fall significantly below the global average. Long-term climate evolution simulations indicate that in these circumstances, water ice is transported to the highlands from low-lying regions for a wide range of orbital obliquities, regardless of the extent of the Tharsis bulge. In addition, an extended water ice cap forms on the southern pole, approximately corresponding to the location of the Noachian/Hesperian era Dorsa Argentea Formation. Even for a multiple-bar CO 2 atmosphere, conditions are too cold to allow long-term surface liquid water. Limited melting occurs on warm summer days in some locations, but only for surface albedo and thermal inertia conditions that may be unrealistic for water ice. Nonetheless, meteorite impacts and volcanism could potentially cause intense episodic melting under such conditions. Because ice migration to higher altitudes is a robust mechanism for recharging highland water sources after such events, we suggest that this globally sub-zero, ‘icy highlands’ scenario for the late Noachian climate may be sufficient to explain most of the fluvial geology without the need to invoke additional long-term warming mechanisms or an early warm, wet Mars.

Subfields: Astronomy and Astrophysics, Environmental Chemistry

View Paper: https://www.semanticscholar.org/paper/31ec2ac5d95cd44f5f4b815b526ca3a805df7be3

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Citations in the corpus

3D climate modeling of close-in land planets: Circulation patterns, climate moist bistability and habitability (2013, methodology): “Because sublimation/condensation processes are constantly occurring, this ice surface density may continue to evolve, but on a much longer time scale that is difficult to model (see Wordsworth et al. 2013 for a discussion).”
Modeling climate diversity, tidal dynamics and the fate of volatiles on TRAPPIST-1 planets (2017, background): “Note that more details on the LMD Generic model can be found in Forget et al. (1999), Wordsworth et al. (2011), Forget et al. (2013), Wordsworth et al. (2013), Charnay et al. (2013), Leconte et al. (2013a), Turbet et al. (2016) and Turbet et al. (2017a).”
Exploring the faint young Sun problem and the possible climates of the Archean Earth with a 3‐D GCM (2013, positive): “This model has been used to study early climates in the solar system [ Forget et al. , 2012; Wordsworth et al. , 2012] as well as climates on extrasolar planets [ Wordsworth et al. , 2011; Leconte et al. , 2013].”
Comparison of “warm and wet” and “cold and icy” scenarios for early Mars in a 3‐D climate model (2015, background): “This causes the equatorial highlands to be among the coldest regions of the Martian surface, leading to enhanced stability of snow deposits there (the ‘icy highlands’ effect [Wordsworth et al., 2013]).”
3D modelling of the early Martian Climate under a denser CO2 atmosphere: Temperatures and CO2 ice clouds. (2012, background): “D radiative convective model, they had shown that a 5-bar gaseous CO2 atmosphere would raise the global mean surface temperature to 0◦C, allowing “warm and wet” conditions (though large, 5 bars of CO2 was still consistent with contempory estimates of the available inventory).”
The Climate of Early Mars (2016, methodology): “Wordsworth et al. (2015) tried both these approaches to study precipitation patterns on a warm and wet early Mars.”
The habitability of Proxima Centauri b II. Possible climates and Observability (2016, background): “Low irradiated planets as Early Mars (Forget et al. 2013; Wordsworth et al. 2013, 2015; Turbet et al. 2016b), Archean Earth (Charnay et al. 2013), Snowball Earth-like planets (Turbet et al. 2016a) or exoplanets like Gliese 581d (Wordsworth et al. 2011); 2.”
Transient reducing greenhouse warming on early Mars (2016, positive): “Note that 273 K may be an upper limit on the global mean temperature required to explain valley network formation due to the importance of local and seasonal eﬀects in determining runoﬀ [see, e.g., Wordsworth et al. , 2013; Kite et al. , 2013; Rosenberg and Head , 2015].”
Geologic Constraints on Early Mars Climate (2018, background): “But maximum CO2 + H2O(v) warming is too cold for H2O(l) rivers (Forget et al. 2013, Wordsworth et al. 2013, Turbet & Tran 2017).”