An investigation into the stochastic physics of iceberg calving and universal calving laws

冰山崩解的随机物理和通用崩解定律的研究

• 批准号: 1064535
• 负责人: Jeremy Bassis
• 金额: $ 19.93万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1064535&HistoricalAwards=false
• 关键词: investigation; into; stochastic; physics; iceberg

Given the sensitivity of glacier dynamics to the position of the glacier front, without a parameterization of calving, to determine the position of the glacier front, which can be implemented into continental scale ice sheet models, our ability to accurately forecast changes in sea level from the ice sheets in response to climate change will be seriously compromised. However, despite the important role iceberg calving plays in contributing to observed changes in Greenland and Antarctica, the glaciology community still does not have a parameterization of iceberg calving that can explain the diversity of observed calving behavior. The challenge that must be overcome is that the parameterization of calving must not only be capable of explaining the wide variety of observed behaviors, it must also be sufficiently simple that it can be incorporated into continental-scale ice sheet models without introducing a prohibitive computational tax on the models and modelers. Funds are provided to develop a parameterization of calving that (i) can be applied to grounded and floating glacier termini and (ii) can be implemented into regional and/or continental scale ice-sheet-shelf models. The primary goal is not to predict the specific behavior of a particular outlet glacier, but instead to attack the problem from a broader perspective and try to understand the qualitative envelope of behavior and stability of ice tongues, outlet and tidewater glaciers as a group. The calving law will be formulated as a stochastic process using techniques borrowed from the statistical-mechanical theory of fracture of disordered material. The newly derived calving law will be incorporated into a flowline ice-sheet-shelf model to simulate a range of different environmental conditions, basal topographies, and sliding laws. The core of this proposal focuses on determining the behavior predicted by the calving law throughout the entire range of parameter space.

鉴于冰川动力学对冰川锋面位置的敏感性，如果不对崩解进行参数化，就可以确定冰川锋面的位置，这可以应用到大陆尺度的冰盖模型中，我们根据冰盖准确预测海平面变化以应对气候变化的能力将受到严重影响。然而，尽管冰山崩解对格陵兰和南极洲的观测变化起到了重要作用，冰川学界仍然没有冰山崩解的参数来解释观测到的冰川崩解行为的多样性。必须克服的挑战是，冰解的参数化不仅必须能够解释观察到的各种行为，而且还必须足够简单，以便能够将其纳入大陆规模的冰盖模型，而不会对模型和模型师征收令人望而却步的计算税。提供了资金，以开发一种冰解的参数，(1)可应用于搁浅和漂浮的冰川终点站，(2)可用于区域和/或大陆范围的冰盖-陆架模型。主要目标不是预测特定出口冰川的具体行为，而是从更广泛的角度来解决这个问题，并试图了解冰舌、出口冰川和潮水冰川作为一个整体的行为和稳定性的定性包络。利用从无序材料断裂的统计力学理论中借用的技术，崩解定律将被描述为一个随机过程。新得出的崩解定律将被纳入流线冰盖-陆架模型中，以模拟一系列不同的环境条件、基本地形和滑动规律。这一建议的核心是确定在整个参数空间范围内由解冻定律预测的行为。