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%的水通过周围的冰架和终止水的冰川排出。冰山崩解是冰损失的主要机制，并以断裂为先决条件。通常，裂缝在加速的冰流的上游形成，并沿着冰架的剪切边缘，并与冰一起被带到崩解锋。我们已经开发了一种模型方法，可以解释冰架裂缝的形成，增长和运输，并将结果与可见的卫星观测结果进行比较。我们进一步引入了冰流和断裂过程的宏观耦合，这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。通过使用克莉丝汀韦舍（AWI）提供的现场数据和空中观测的新见解，我们希望量化预期的冰山释放的平均大小和频率。我们将明确地解释裂缝的垂直增长和裂缝的水平扩展，然后才分离成冰山。我们将应用这种增强的产犊参数化在模拟南极冰盖的时期以来的最后一次冰期最大（LGM）。与迈克尔韦伯和鲁珀特格莱斯顿合作，我们想研究模拟冰山与沿岸流的运输，比较计算的冰山通量与古沉积物数据。这一示范活动将使人们全面了解过去的快速变化以及在未来气候变化中可能作出的动态反应。