The influence of fracture-induced calving on Antarctica's contribution to future sea-level change

裂缝引起的崩解对南极洲未来海平面变化的影响

• 批准号: 257497716
• 负责人: Professor Dr. Anders Levermann
• 金额: --
• 依托单位: Potsdam-Institut für Klimafolgenforschung (PIK)
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/257497716?language=en
• 关键词: influence; fracture; induced; calving; Antarctica

The Antarctic ice sheet is drained to about 90% through the surrounding ice shelves and water-terminating glaciers. Iceberg calving is a major mechanism of ice loss and is preconditioned by fractures. Usually fractures form far upstream in accelerating ice streams and along the shear margins of the ice shelves and are transported in bands with the ice towards the calving front. We have already developed a model approach that accounts for the formation, growth and transport of fractures in ice shelves and compared the results to visible satellite observation. We further introduced a macroscopic coupling of ice flow and fracture processes, which represents a potentially self-amplifying feedback mechanism and provides explanations for several observed features of ice flow.Based on the previous work we want to expand the fracture-density approach and derive a fracture-coupled calving parameterization. By using new insights from field data and airborne observations, provided by Christine Wesche (AWI), we would like to quantify expected average size and frequency of iceberg release. We will account explicitly for the vertical growth of cracks and horizontal propagation of rifts before getting detached as icebergs. We will apply this enhanced calving parameterization in a simulation of the Antarctic ice sheet for the period since the Last Glacial Maximum (LGM). In collaboration with Michael Weber and Rupert Gladstone we would like to study the transport of simulated icebergs with the coastal current to compare the computed iceberg fluxes with paleo sediment data. This model exercise would provide a holistic understanding of fast changes in the past and possible dynamic responses in a changing future climate.

南极冰盖约 90% 的水分是通过周围的冰架和断水冰川排出的。冰山崩解是冰损失的主要机制，并且以破裂为先决条件。通常，裂缝在加速冰流的上游很远的地方形成，并沿着冰架的剪切边缘形成，并与冰一起向崩解前缘输送。我们已经开发了一种模型方法，可以解释冰架裂缝的形成、生长和传输，并将结果与​​可见卫星观测结果进行比较。我们进一步引入了冰流和裂缝过程的宏观耦合，它代表了一种潜在的自放大反馈机制，并为冰流的几个观察到的特征提供了解释。基于之前的工作，我们希望扩展裂缝密度方法并推导出一个断裂耦合崩解参数化。通过使用 Christine Wesche (AWI) 提供的现场数据和机载观测的新见解，我们希望量化冰山释放的预期平均大小和频率。在像冰山一样分离之前，我们将明确考虑裂缝的垂直增长和裂痕的水平扩展。我们将在自末次盛冰期 (LGM) 以来的南极冰盖模拟中应用这种增强的崩解参数化。我们希望与迈克尔·韦伯和鲁珀特·格拉德斯通合作，研究模拟冰山随沿海流的迁移，以将计算出的冰山通量与古沉积物数据进行比较。该模型练习将提供对过去快速变化以及未来气候变化中可能的动态响应的整体理解。