Ice-Shelf Rift Propagation: Computational Simulation Using a Fracture Fracture Mechanics Approach

该奖项支持一个项目，该项目旨在开发计算模型，以模拟冰架裂隙的传播，使用基于线弹性断裂力学(LEFM)的成熟的冰架蠕变流动模型和新的裂隙模型的组合。这项拟议工作的总体目标是模拟裂谷传播和最终的大型冰山崩解，并将这些过程置于更大的冰盖和气候背景下。这项工作将分阶段进行，首先开发单个和多个裂缝传播的模型；然后使用这些模型来评估传播对各种环境条件的敏感性；以及第三个开发既包括裂缝传播又包括冰架系统内平流的模型。模型的开发将根据卫星对南极冰架上几个特征位置的裂谷传播的观测进行指导和评估。冰层破裂的新数值模型将应用于冰川学中的许多问题。这里提出的研究是针对冰架上的大裂缝形成和随后的冰山崩解。它的动机是需要了解现代冰架观察到的变化，以及它们与气候的联系。在已经取样的地方，韦德尔海部分的沉积记录表明，半岛冰架在千年时间尺度上具有变异性。以可信的方式模拟冰山崩解的能力将提高我们再现此类事件的能力，并将冰架进退的整个周期置于冰动力学背景下。反过来，这将使我们能够将冰架循环置于气候循环中，最终推动冰盖质量平衡。

This award supports a project to develop computational models to simulate ice-shelf rift propagation using a combination of well-established ice-shelf creep-flow models and new crevasse models, based on linear elastic fracture mechanics (LEFM). The overall objective of the proposed work is to simulate rift propagation and eventual large iceberg calving,and place those processes within a larger ice sheet and climate context. The work will proceed in stages, first developing models of single-and multiple-crevasse propagation; then using those models to evaluate propagation sensitivity to various environmental conditions; and third developing models that incorporate both crevasse propagation and advection within an ice- shelf system. Model development will be guided by and evaluated according to satellite observations of rift propagation in several characteristic locations on Antarctic ice shelves. New numerical models of fracture in ice will have applications to many problems in glaciology. The research proposed here is directed toward large rift formation in ice shelves and subsequent iceberg calving. It is motivated by the need to understand observed changes in modern ice shelves,and their connection to climate. Where it has been sampled, the sedimentary record of the Weddell Sea sector implies Peninsular ice shelf variability on millennial time scales. The ability to simulate iceberg calving in a credible way will improve our ability to reproduce such events and place the complete cycle of ice shelf advance and retreat in an ice-dynamics context. That will, in turn, enable us to place ice-shelf cycles within the climate cycles that ultimately drive ice-sheet mass balance.