Physical modeling of the influence of bedrock topography and ablation on ice flow and meteorite concentration in Antarctica
Physical modeling of the influence of bedrock topography and ablation on ice flow and meteorite concentration in Antarctica
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DOI：
10.1029/2006jf000708
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发表时间：
2008-03-13
影响因子：
3.9
通讯作者：
Folco, Luigi
中科院分区：
文献类型：
--
作者：
Corti, Giacomo;Zeoli, Antonio;Folco, Luigi
利用三维室内物理实验研究了基岩地形和消融对冰流的影响。不同的模型在一个有机玻璃盒子里进行了测试，在这个盒子里，一种模拟自然冰的透明硅胶被允许流动。实验结果表明，流场（流线和流速）以及冰的自由表面和内层的地形变化如何受到基岩障碍物的存在和高度的强烈影响。特别是，支撑效应迫使冰减速，上升，避开障碍物；基岩屏障越高，这个过程就越明显。在这些实验中只观察到有限的内层隆起。为了挖掘埋在冰中的深层物质，物理模型中必须包括烧蚀（通过物理移除模型表面的部分硅树脂以保持恒定的地形凹陷来模拟）。在这种情况下，模拟冰补充了材料去除的区域，从而允许深层垂直移动到表面，并严重改变了局部冰流模式。这一过程类似于文献中提出的南极高原蓝色冰区陨石浓度起源的冰流模型。
Three-dimensional laboratory physical experiments have been used to investigate the influence of bedrock topography and ablation on ice flow. Different models were tested in a Plexiglas box, where a transparent silicone simulating ice in nature was allowed to flow. Experimental results show how the flow field (in terms of both flow lines and velocity) and variations in the topography of the free surface and internal layers of the ice are strongly influenced by the presence and height of bedrock obstacles. In particular, the buttressing effect forces the ice to slow down, rise up, and avoid the obstacle; the higher the bedrock barrier, the more pronounced the process. Only limited uplift of internal layers is observed in these experiments. In order to exhume deep material embedded in the ice, ablation (simulated by physically removing portions of silicone from the model surface to maintain a constant topographic depression) must be included in the physical models. In this case, the analogue ice replenishes the area of material removal, thereby allowing deep layers to move vertically to the surface and severely altering the local ice flow pattern. This process is analogous to the ice flow model proposed in the literature for the origin of meteorite concentrations in blue ice areas of the Antarctic plateau.