Ice-flow sensitivity to boundary processes: a coupled model study in the Vostok Subglacial Lake area, Antarctica
Ice-flow sensitivity to boundary processes: a coupled model study in the Vostok Subglacial Lake area, Antarctica
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冰流对边界过程的敏感性：南极洲沃斯托克冰下湖地区的耦合模型研究
DOI：
10.3189/2012aog60a009
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发表时间：
2012
影响因子：
2.9
通讯作者：
F. Pattyn
中科院分区：
文献类型：
--
作者：
M. Thoma;K. Grosfeld;C. Mayer;F. Pattyn
到目前为止，已在南极洲地下发现了数百个冰下湖泊。它们与上覆冰盖的相互作用以及它们对冰动力学的影响仍然是研究的主题。虽然已知湖泊减少了冰盖向自由滑动基本边界条件下的摩擦，但湖/冰界面的基础融化和冻结如何改变冰的动力学、热状况和冰的流变性却知之甚少。在这项诊断性研究中，我们用一个耦合的全Stokes三维冰流模型和一个三维湖泊环流模型来模拟Vostok冰下湖区。在冰冻(融化)地区，湖/冰界面的能量(热)和质量交换使湖面上方冰柱的温度增加(降低)10%，导致高度非线性的冰粘度发生显著变化。结果表明，冰盖底部的基础润滑不仅对湖面上方的冰流有显著的影响，而且对近、远场也有显著的影响。当冰流穿过沃斯托克冰下湖泊时，观测到了水流分流并对其进行了模拟。湖/冰界面的非均质物质平衡模式加剧了这种差异。与冰流模型和湖流模型之间的交互耦合不同，只需要一次迭代就可以真实地表示冰/水相互作用。此外，我们的研究表明，地表温度边界条件的简化可能会导致研究区的速度误差为20%。
Abstract Several hundred subglacial lakes have been identified beneath Antarctica so far. Their interaction with the overlying ice sheet and their influence on ice dynamics are still subjects of investigation. While it is known that lakes reduce the ice-sheet friction towards a free-slip basal boundary condition, little is known about how basal melting and freezing at the lake/ice interface modifies the ice dynamics, thermal regime and ice rheology. In this diagnostic study we simulate the Vostok Subglacial Lake area with a coupled full Stokes 3-D ice-flow model and a 3-D lake-circulation model. The exchange of energy (heat) and mass at the lake/ice interface increases (decreases) the temperature in the ice column above the lake by up to 10% in freezing (melting) areas, resulting in a significant modification of the highly nonlinear ice viscosity. We show that basal lubrication at the bottom of the ice sheet has a significant impact not only on the ice flow above the lake itself, but also on the vicinity and far field. While the ice flow crosses Vostok Subglacial Lake, flow divergence is observed and modelled. The heterogeneous basal-mass-balance pattern at the lake/ice interface intensifies this divergence. Instead of interactive coupling between the ice-flow model and the lake-flow model, only a single iteration is required for a realistic representation of the ice/water interaction. In addition, our study indicates that simplified parameterizations of the surface temperature boundary condition might lead to a velocity error of 20% for the area of investigation.
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模拟南极洲冰下沃斯托克湖的混合和循环
影响因子：
2.3
作者：
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通讯作者：
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影响因子：
5.3
作者：
I. Filina;D. Blankenship;M. Thoma;V. Lukin;V. N. Masolov;Mrinal K. Sen
通讯作者：
I. Filina;D. Blankenship;M. Thoma;V. Lukin;V. N. Masolov;Mrinal K. Sen
影响因子：
5.2
作者：
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通讯作者：
J. Woodward;A. Smith;N. Ross;M. Thoma;H. Corr;E. King;Matt A. King;K. Grosfeld;M. Tranter;M. Siegert
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影响因子：
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作者：
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通讯作者：
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影响因子：
5.3
作者：
Grosfeld
通讯作者：
Grosfeld