Automated feature detection and hydrocode modeling of impact-related structures on Mars
Automated feature detection and hydrocode modeling of impact-related structures on Mars
复制标题
火星撞击相关结构的自动特征检测和水电编码建模
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
C. Plesko
中科院分区：
文献类型：
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作者：
C. Plesko
在过去的二十年里，大量的证据已经积累了火星表面上液态水的存在和持久性，从最古老的可观测表面到大约35亿年前。现代火星上液态水的存在只有在特殊的情况下才有可能，而对于古代火星来说，这些情况进一步受到标准太阳模型的预测的限制，即太阳在当时明显较暗。卡尔（1996）[95]和塞古拉等人（2002）[403]认为大的小行星和彗星撞击可能是火星历史早期温暖和潮湿气候的触发因素。我的目标是模拟影响到地层复杂的介质，特别是目标含有水冰在各种形态，以确定一个下限的能量和大小尺度的影响事件，可能会引发这样的气候变化，从而建立一个上限的频率这样的事件。为此，我使用了各种分析和数值建模技术，包括Escherichia Hydrocode [292]是一种欧拉水动力学代码，它运行在三维空间，并包含各种状态方程，包括LANL维护的SEEscherichia Table。为了在将其应用于问题之前测试预测的准确性。我将代码结果与问题相关的分析模型（验证）和实验室实验（验证）进行比较。具体来说，我比较了实验（[392]，[358]）和分析陨石坑缩放模型（[226]，[221]，[218]和[322]）。从那里，我研究水冰在火星地下的影响的潜在影响，首先通过研究的温度和压力剖面的影响到一个地质简单，无冰的目标的演变，然后探索冰含量和形态的影响。
A substantial amount of evidence has accumulated over the past two decades for the presence and persistence of liquid water on the surface of Mars early in its history—from the oldest observable surfaces up to approximately 3.5 billion years ago. The presence of liquid water on modern Mars is possible only under peculiar circumstances, and for ancient Mars these circumstances are further limited by predictions of the Standard Solar Model that the Sun was significantly fainter at that time. Large asteroid and comet impacts have been suggested by Carr (1996) [95] and Segura et al. (2002) [403] as a possible triggers of warm and wet climate episodes early in Martian history. My goal is to model impacts into stratigraphically complicated media, specifically targets containing water ice in various morphologies, in order to determine a lower bound on the energy and size scales of impact events that could trigger such a climate shift, and thus establish an upper bound on the frequency of such events. To do this, I used various analytical and numerical modeling techniques, including the RAGE hydrocode RAGE [292] is an Eulerian hydrocode that runs in up to three dimensions and incorporates a variety of equations of state including the SESAME tables maintained by LANL. In order to test the accuracy of RAGE predictions before applying it to the problem. I compare code results against analytical models (verification) and laboratory experiments (validation) that are related to the problem. Specifically, I compare RAGE against experiments ([392], [358]), and analytical crater scaling models ([226], [221], [218], and [322]). From there, I examine the potential effects of impacts on water ice in the Martian subsurface, first by examining the evolution of the temperature and pressure profiles of an impact into a geologically simple, ice-free target, and then exploring the effects of ice content and morphology.