Interaction between ice sheet dynamics and subglacial lake circulation: a coupled modelling approach
Interaction between ice sheet dynamics and subglacial lake circulation: a coupled modelling approach
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DOI：
10.5194/tc-4-1-2010
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发表时间：
2010-01-01
期刊：
影响因子：
5.2
通讯作者：
Pattyn, F.
中科院分区：
文献类型：
--
作者：
Thoma, M.;Grosfeld, K.;Pattyn, F.
南极的冰下湖泊在很大程度上影响着冰盖的流动。在这项研究中，我们使用一种理想化的湖泊几何形状来研究这种影响。我们采用了：a)一个具有非线性流变学的改进的三维全斯托克斯冰流模型，b)一个带有涡动扩散的三维流体动力学模型来模拟湖 - 冰界面的基底物质平衡，以及c)一个新开发的耦合器来在两个独立模型之间交换边界条件。在接地冰和浮冰上应用了不同的边界条件。这导致湖泊上方冰内的温度相较于湖区外相同深度的冰显著升高。冰盖的底部融化加剧了这种横向温度梯度。在湖的上游，冰流朝着湖泊汇聚，并且只要在冰 - 湖边界存在底部融化，冰流就会加速约10%。在湖泊的上方和下游，即冰流发散的地方，模拟出速度降低了约10%。
Subglacial lakes in Antarctica influence to a large extent the flow of the ice sheet. In this study we use an idealised lake geometry to study this impact. We employ a) an improved three-dimensional full-Stokes ice flow model with a nonlinear rheology, b) a three-dimensional fluid dynamics model with eddy diffusion to simulate the basal mass balance at the lake-ice interface, and c) a newly developed coupler to exchange boundary conditions between the two individual models. Different boundary conditions are applied over grounded ice and floating ice. This results in significantly increased temperatures within the ice on top of the lake, compared to ice at the same depth outside the lake area. Basal melting of the ice sheet increases this lateral temperature gradient. Upstream the ice flow converges towards the lake and accelerates by about 10% whenever basal melting at the ice-lake boundary is present. Above and downstream of the lake, where the ice flow diverges, a velocity decrease of about 10% is simulated.