TY - JOUR
T1 - A coupled atmosphere–hydrosphere global climate model of early Mars
T2 - A ‘cool and wet’ scenario for the formation of water channels
AU - Kamada, A.
AU - Kuroda, T.
AU - Kasaba, Y.
AU - Terada, N.
AU - Nakagawa, H.
AU - Toriumi, K.
N1 - Funding Information:
We would like to our sincere appreciation for the reviews and scientific suggestion provided by I. Murata. We thank A. Nitta, T. Akiba, A. Hubig and all other former and present members in the laboratory of Planetary Atmospheric Science, Tohoku University. AK was supported by the Yoshida Scholarship Foundation, Master 21. TK is supported by Grant-in-Aid for Scientific Research (C) 16K05552 from the Japan Society for the Promotion of Science (JSPS). YK, TK, HN and NT are supported by Grant-in-Aid for Scientific Research (A) 19H00707 from JSPS. NT and TK are supported by the Astrobiology Center Program of National Institutes of Natural Sciences (NINS) (Grant Number AB312005). NT was supported by Grant-in-Aid for Scientific Research (B) 15H03731 and for Scientific Research (A) 16H02229 from JSPS. HN was supported by the Astrobiology Center Program of NINS (Grant Number AB291015), and Grant-in-Aid for Scientific Research (C) 16K05566 from JSPS. YK, TK and HN also thank to Japan - Belgium (F.R.S.-FNRS) Joint Research Projects under the Bilateral Program “Exploring the Atmosphere of MArs and VEnus with Remote Observations”. The model runs have been performed with FUJITSU FX10 (Oakleaf-FX) and HITACHI SR16000 (yayoi) systems at the Information Technology Center, The University of Tokyo, and FUJITSU PRIMERGY CX 2550 (ITO) system at the Research Institute for Information Technology, Kyushu University. Fruitful comments by E. Kite of University of Chicago and one anonymous reviewer helped to sophisticate the discussions on this paper.
Funding Information:
We would like to our sincere appreciation for the reviews and scientific suggestion provided by I. Murata. We thank A. Nitta, T. Akiba, A. Hubig and all other former and present members in the laboratory of Planetary Atmospheric Science, Tohoku University. AK was supported by the Yoshida Scholarship Foundation, Master 21. TK is supported by Grant-in-Aid for Scientific Research (C) 16K05552 from the Japan Society for the Promotion of Science (JSPS). YK, TK, HN and NT are supported by Grant-in-Aid for Scientific Research (A) 19H00707 from JSPS . NT and TK are supported by the Astrobiology Center Program of National Institutes of Natural Sciences (NINS) (Grant Number AB312005 ). NT was supported by Grant-in-Aid for Scientific Research (B) 15H03731 and for Scientific Research (A) 16H02229 from JSPS . HN was supported by the Astrobiology Center Program of NINS (Grant Number AB291015 ), and Grant-in-Aid for Scientific Research (C) 16K05566 from JSPS . YK, TK and HN also thank to Japan - Belgium (F.R.S.-FNRS) Joint Research Projects under the Bilateral Program “Exploring the Atmosphere of MArs and VEnus with Remote Observations”. The model runs have been performed with FUJITSU FX10 (Oakleaf-FX) and HITACHI SR16000 (yayoi) systems at the Information Technology Center, The University of Tokyo, and FUJITSU PRIMERGY CX 2550 (ITO) system at the Research Institute for Information Technology, Kyushu University. Fruitful comments by E. Kite of University of Chicago and one anonymous reviewer helped to sophisticate the discussions on this paper.
Publisher Copyright:
© 2019
PY - 2020/3/1
Y1 - 2020/3/1
N2 - Martian water channels are considered evidence of a climate warm enough to allow the existence of long-term fluvial systems on early Mars during the Noachian and Hesperian boundary (3.85–3.6 Ga). Quantitative inferences of water channel formation from climate models are crucial to develop an accurate understanding of the early Martian environment. We present the results of a newly developed 3-dimensional Paleo Martian Global Climate Model (PMGCM) assuming a CO2/H2O/H2 atmosphere under the ‘Faint Young Sun’ condition (with a solar luminosity of ~75% of the current value) for surface pressures between 0.5 and 2 bar. The PMGCM has a hydrologic cycle module, which includes ocean thermodynamics and water vapor advection, convection, condensation and precipitation processes, as well as calculations of surface fluvial activities (e.g., fluvial activity and sediment transport) at a high horizontal resolution. Our PMGCM results show that the early Martian surface environment could have been ‘cool’ (between ‘warm’ and ‘cold’); namely, the surface temperatures could have been high enough (>273 K) during summertime to allow seasonal melting of snow and ice deposits, and low enough (<273 K) during wintertime to produce considerable snow precipitation and accumulation, under the conditions of a mean surface pressure of approximately 1.5 bar and an H2 composition of 3%. The results also indicate that a ‘wet’ surface environment should be characterized by precipitation and seasonal melting of snow and ice (neither ‘dry’ nor ‘permanently frozen’ states), and enough fluvial activity and sediment transport could have occurred in the low to middle latitudes to produce Martian valley networks within a relatively short time (less than tens of million years). Therefore, we suggest that a moderate climate, that is, ‘cool and wet’ conditions lying between ‘warm and wet’ and ‘cold and frozen’, best explains the fluvial activity on early Mars.
AB - Martian water channels are considered evidence of a climate warm enough to allow the existence of long-term fluvial systems on early Mars during the Noachian and Hesperian boundary (3.85–3.6 Ga). Quantitative inferences of water channel formation from climate models are crucial to develop an accurate understanding of the early Martian environment. We present the results of a newly developed 3-dimensional Paleo Martian Global Climate Model (PMGCM) assuming a CO2/H2O/H2 atmosphere under the ‘Faint Young Sun’ condition (with a solar luminosity of ~75% of the current value) for surface pressures between 0.5 and 2 bar. The PMGCM has a hydrologic cycle module, which includes ocean thermodynamics and water vapor advection, convection, condensation and precipitation processes, as well as calculations of surface fluvial activities (e.g., fluvial activity and sediment transport) at a high horizontal resolution. Our PMGCM results show that the early Martian surface environment could have been ‘cool’ (between ‘warm’ and ‘cold’); namely, the surface temperatures could have been high enough (>273 K) during summertime to allow seasonal melting of snow and ice deposits, and low enough (<273 K) during wintertime to produce considerable snow precipitation and accumulation, under the conditions of a mean surface pressure of approximately 1.5 bar and an H2 composition of 3%. The results also indicate that a ‘wet’ surface environment should be characterized by precipitation and seasonal melting of snow and ice (neither ‘dry’ nor ‘permanently frozen’ states), and enough fluvial activity and sediment transport could have occurred in the low to middle latitudes to produce Martian valley networks within a relatively short time (less than tens of million years). Therefore, we suggest that a moderate climate, that is, ‘cool and wet’ conditions lying between ‘warm and wet’ and ‘cold and frozen’, best explains the fluvial activity on early Mars.
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U2 - 10.1016/j.icarus.2019.113567
DO - 10.1016/j.icarus.2019.113567
M3 - Article
AN - SCOPUS:85104617015
VL - 338
JO - Icarus
JF - Icarus
SN - 0019-1035
M1 - 113567
ER -