arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1405.6701astro-ph.EP
收藏

用CO2和H2使早期火星变暖

Warming early Mars with CO2 and H2

Ramses M. Ramirez, Ravi Kopparapu, Michael E. Zugger, Tyler D. Robinson, Richard Freedman, James F. Kasting

摘要:

火星古代地形上山谷的存在表明,38亿年前或更早以前,火星表面曾有液态水流动。解释山谷形成所需的冰点以上的温度可能是短暂的,这是对早期火星上频繁的大型陨石撞击的反应,或者它们可能是由长期的温室效应造成的。由于当时太阳光度较低,只考虑温室气体二氧化碳和水蒸气的气候模型无法重现温暖的地表条件。在这里,我们使用一个一维气候模型来证明,一个含有1.3-4 bar的二氧化碳和水蒸气,以及5%到20%的氢气的大气层,可能会使早期火星的平均地面温度升高到水的冰点以上。从高度还原的早期火星地幔的火山喷发,预计将提供足够的大气H2和CO2,后者从光化学氧化的CH 4和CO,形成CO2-H2温室。如此稠密的早期火星大气层与基于陨石坑数据对表面压力的独立估计是一致的。

英文摘要:

The presence of valleys on ancient terrains of Mars suggest that liquid water flowed on the martian surface 3.8 billion years ago or before. The above-freezing temperatures required to explain valley formation could have been transient, in response to frequent large meteorite impacts on early Mars, or they could have been caused by long-lived greenhouse warming. Climate models that consider only the greenhouse gases carbon dioxide and water vapor have been unable to recreate warm surface conditions, given the lower solar luminosity at that time. Here we use a one-dimensional climate model to demonstrate that an atmosphere containing 1.3-4 bar of CO2 and water vapor, along with 5 to 20 percent H2, could have raised the mean surface temperature of early Mars above the freezing point of water. Vigorous volcanic outgassing from a highly reduced early martian mantle is expected to provide sufficient atmospheric H2 and CO2, the latter from the photochemical oxidation of outgassed CH4 and CO, to form a CO2-H2 greenhouse. Such a dense early martian atmosphere is consistent with independent estimates of surface pressure based on cratering data.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑