Temporary liquid water in upper snow/ice sub-surfaces on Mars?
Temporary liquid water in upper snow/ice sub-surfaces on Mars?
复制标题
火星上层雪/冰地下存在临时液态水？
DOI：
10.1016/j.icarus.2009.11.013
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发表时间：
2010
期刊：
影响因子：
3.2
通讯作者：
D. Möhlmann
中科院分区：
文献类型：
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作者：
D. Möhlmann
研究人员研究了在火星表面温度低于零度的情况下，是否可以通过固态温室效应在火星上的冰雪覆盖地区暂时创造融化的条件。这种可能的暂时融化的条件被定量地描述为A=0.8和A=0.2的辐射反照率值，以及目前火星表面冰雪点的典型热物理条件的模式参数。数值模拟表明，有几组参数将导致火星上的雪和冰的顶部表面以下的液态水层的发展。这种至少部分液化是重复发生的（例如，每天，季节性地），在某些情况下可能导致液态水在夏季的夜间持续存在。这种液态水可以形成足够的量，与宏观物理（流变学，侵蚀），化学，最终也与生物过程相关。由于这种影响而产生的暂时的地下水袋需要预先存在的雪或冰覆盖，因此更有可能发生在高纬度地区，因为目前的雪/冰沉积主要在那里。根据目前对近期流变过程的观测，讨论了火星雪/冰袋中液态水的出现可能造成的流变和相关侵蚀后果。
It is investigated whether conditions for melting can be temporarily created in the upper sub-surface parts of snow/ice-packs on Mars at subzero surface temperatures by means of the solid-state greenhouse effect, as occurs in snow- and ice-covered regions on Earth. The conditions for this possible temporary melting are quantitatively described for bolometric albedo values A=0.8 and A=0.2, and with model parameters typical for the thermo-physical conditions at snow/ice sites on the surface of present Mars. It is demonstrated by numerical modelling that there are several sets of parameters which will lead to development of layers of liquid water just below the top surface of snow- and ice-packs on Mars. This at least partial liquefaction occurs repetitively (e.g. diurnally, seasonally), and can in some cases lead to liquid water persisting through the night-time in the summer season. This liquid water can form in sufficient amounts to be relevant for macroscopic physical (rheology, erosion), for chemical, and eventually also for biological processes. The creation of temporary pockets of sub-surface water by this effect requires pre-existing snow or ice cover, and thus is more likely to take place at high latitudes, since the present deposits of snow/ice can mainly be found there. Possible rheologic and related erosion consequences of the appearance of liquid sub-surface water in martian snow/ice-packs are discussed in view of current observations of recent rheologic processes.