Fracture: At the frontier of Antarctica's contribution to sea level

断裂：位于南极洲对海平面贡献的前沿

• 批准号: NE/X011372/1
• 负责人: Robert Arthern
• 金额: $ 12.52万
• 依托单位: British Antarctic Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX011372%2F1
• 关键词: Fracture; frontier; Antarctica; contribution; sea

In this proposal we are seeking funding to make a leap towards simulating fracture within the Antarctic Ice Sheet on the scales that will be needed to address the problem of predicting global sea level. The largest source of uncertainty in projections of sea level over the coming century is due to the Marine Ice Cliff Instability. This is the name given to a particular mode of failure of the Antarctic ice sheet in which large ice cliffs collapse due to fracture, exposing even taller cliffs, thus leading to an ever accelerating loss of ice to the ocean. The physical models needed to simulate this process in predictive models of the sea level contribution from Antarctica are presently based upon heuristic assumptions that use cliff collapse rates observed in a few outlet glaciers. There is no guarantee that this approach will correctly predict the loss of ice from Antarctica. A more rigorous approach is needed. In this proposal we aim to simulate the collapse of ice cliffs using equations that describe the physical process of fracture in a viscoelastic material. We have already developed a detailed model of this process that uses a phase-field approach to simulate the mechanical failure of a calving ice front. We also have a model of the slow viscous component of the ice flow that evolves the ice sheet on a regional scale. The actual failure of the ice sheet and the sea level contribution will involve both the rapid fracture processes and the slower viscous flow, so there is an urgent need to combine the strengths of both models. In this project, we propose to couple the phase-field approach within the broad-scale ice model in a way that preserves the advantage of each. We hope that this will establish a path for other ice sheet modelling groups to follow so that projections of the worst case for sea level rise are not subject to the enormous uncertainty from the Marine Ice Cliff Instability that they are today.

在这项提案中，我们正在寻求资金，以便在解决预测全球海平面问题所需的规模上，实现模拟南极冰盖断裂的飞跃。未来世纪海平面预测的最大不确定性来源是海洋冰崖不稳定性。这是南极冰盖的一种特殊破坏模式的名称，其中大型冰崖由于断裂而倒塌，暴露出更高的悬崖，从而导致冰不断加速流失到海洋中。在南极洲海平面贡献预测模型中模拟这一过程所需的物理模型目前是基于启发式假设，即使用在少数出口冰川中观察到的悬崖崩塌率。不能保证这种方法能正确预测南极洲冰的流失。需要采取更严格的办法。在这个建议中，我们的目标是使用描述粘弹性材料断裂的物理过程的方程来模拟冰崖的坍塌。我们已经开发了一个详细的模型，这个过程中使用相场的方法来模拟机械断裂的冰锋。我们也有一个模型的缓慢粘性组成部分的冰流演变的冰盖在区域范围内。冰盖的实际破坏和海平面的贡献将涉及快速断裂过程和较慢的粘性流动，因此迫切需要联合收割机结合两种模式的优势。在这个项目中，我们建议在大尺度冰模型中耦合相场方法，以保持各自的优势。我们希望这将为其他冰盖建模小组建立一条道路，以便对海平面上升最坏情况的预测不会受到今天海洋冰崖不稳定性的巨大不确定性的影响。