Grounding line movement and ice shelf buttressing in marine ice sheets
Grounding line movement and ice shelf buttressing in marine ice sheets
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DOI：
10.1029/2008jf001227
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发表时间：
2009-12-23
影响因子：
3.9
通讯作者：
Schoof, C.
中科院分区：
文献类型：
--
作者：
Goldberg, D.;Holland, D. M.;Schoof, C.
了解海洋冰盖的动态对于研究南极冰盖的短期和长期演变都是不可或缺的。动力学的一个重要组成部分，接地线迁移，已被证明难以在数值模型中表示，大多数成功的尝试都使用了只容易适用于流线模型的技术。然而，为了捕捉另一个重要组成部分——由冰架支撑的海洋冰盖——所涉及的应力传递，还必须解决横向的问题。我们介绍了一个模型，该模型解决了时间相关的shelfy流方程，并利用网格自适应技术来克服通常与接地线迁移数值相关的困难。我们将模型输出与最近的流线模型基准进行比较，并表明我们的模型产生准确的解决方案，同时使用的资源远少于没有网格自适应所需的资源。我们还表明，网格适应技术扩展到两个水平维度。进行了实验，以确定冰架支撑和冰上升如何影响预估的深深床上冰盖的海洋不稳定性。我们发现支撑并不总是足以稳定这样的板，但接地部分的坍塌仍然大大延迟。我们还发现，冰上升的影响与缩小冰架的影响相似。
Understanding the dynamics of marine ice sheets is integral to studying the evolution of the Antarctic ice sheet in both the short and long terms. An important component of the dynamics, grounding line migration, has proved difficult to represent in numerical models, and most successful attempts have made use of techniques that are only readily applicable to flow line models. However, to capture the stress transmission involved in another important component, the buttressing of a marine ice sheet by its ice shelf, the transverse direction must also be resolved. We introduce a model that solves the time-dependent shelfy stream equations and makes use of mesh adaption techniques to overcome the difficulties typically associated with the numerics of grounding line migration. We compare the model output with a recent benchmark for flow line models and show that our model yields an accurate solution while using far less resources than would be required without mesh adaption. We also show that the mesh adapting techniques extend to two horizontal dimensions. Experiments are carried out to determine how both ice shelf buttressing and ice rises affect the marine instability predicted for an ice sheet on a foredeepened bed. We find that buttressing is not always sufficient to stabilize such a sheet but collapse of the grounded portion is still greatly delayed. We also find that the effect of an ice rise is similar to that of narrowing the ice shelf.