Collaborative Research: Simulating Iceberg Calving from Ice Shelves using a Damage Mechanics Model

合作研究：使用损伤力学模型模拟冰架崩解的冰山

• 批准号: 1341568
• 负责人: Jeremy Bassis
• 金额: $ 29.29万
• 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: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1341568&HistoricalAwards=false
• 关键词: Collaborative; Research; Simulating; Iceberg; Calving

Bassis/1341568This award supports the development of a model that can simulate both the flow and fracture of glacier ice, (including the slow creeping of that ice) as it spreads under its own weight all the way to the complete failure and detachment (calving) of icebergs from glaciers and ice shelves (floating expanses of glacier ice). Because iceberg calving accounts for nearly 50% of the mass lost from ice shelves, it plays an important role in the mass balance of glaciers and ice sheets, but remains a poorly understood process. Iceberg calving is also not yet accounted for in the current generation of continental-scale ice sheet models, which are used in state-of-the-art climate simulations and sea level rise projections, because simulating iceberg calving requires that we understand the initiation and propagation of fractures within the ice over timescales that can range from a few seconds to decades or even centuries. To address this problem, the primary objective of this project is to address this gap in our understanding by translating physical and computational approaches originally developed to simulate the fracture of quasi-brittle materials, like metals and concrete, to the fracture of glacier ice. Since it is both impossible and impractical to simulate the propagation of each individual crack in an ice sheet, we will seek a "continuum damage mechanics" approach that handles collections of cracks in a physically and thermodynamically consistent way to simulate failure at the large scale. This will be accomplished by using an approach that can simulate what happens to fractures after they form at the interface with the ocean. This project seeks to advance our ability to predict the fate of the Greenland and Antarctic ice sheets and to quantify the ice sheet contribution to sea level rise in the coming centuries. Accomplishing this requires that we have a better understanding of why icebergs that can exceed the size of small New England States, detach and drift away from ice shelves. The broader impacts of the project also include graduate and undergraduate education through directed research projects and targeted engagement of under-represented minorities in low-income regions at the elementary and high school levels. Engagement with under-represented minorities will include counseling and planning for future career paths in the STEM fields and mentoring selected students during summer internship programs hosted by the University of Michigan, Vanderbilt University and Columbia University.

该奖项支持开发一种模型，该模型可以模拟冰川冰的流动和断裂（包括冰的缓慢爬行），因为它在自身重量的作用下一直扩散到冰山和冰架（冰川冰的浮动区域）的完全失败和分离（崩解）。由于冰山崩解占冰架质量损失的近50%，它在冰川和冰盖的质量平衡中起着重要作用，但对这一过程的了解仍然很少。目前的大陆尺度冰盖模型用于最先进的气候模拟和海平面上升预测，但冰山崩解还没有被考虑在内，因为模拟冰山崩解需要我们了解冰层内裂缝的开始和扩展，时间尺度从几秒钟到几十年甚至几个世纪不等。为了解决这个问题，该项目的主要目标是通过将最初用于模拟准脆性材料（如金属和混凝土）断裂的物理和计算方法转化为冰川冰的断裂来解决我们在理解上的这一差距。由于模拟冰盖中每个单独裂缝的扩展既不可能也不现实，我们将寻求一种“连续损伤力学”方法，以物理和热力学一致的方式处理裂缝集合，以模拟大规模的破坏。这将通过一种方法来实现，该方法可以模拟裂缝在与海洋的界面形成后发生的情况。该项目旨在提高我们预测格陵兰和南极冰盖命运的能力，并量化未来几个世纪冰盖对海平面上升的贡献。要做到这一点，我们需要更好地理解为什么冰山可以超过小新英格兰州的大小，从冰架上分离并漂移。该项目的更广泛影响还包括通过有指导的研究项目开展研究生和本科教育，并有针对性地让低收入地区代表性不足的少数民族参与小学和高中教育。与代表性不足的少数族裔的接触将包括为STEM领域的未来职业道路提供咨询和规划，并在密歇根大学、范德比尔特大学和哥伦比亚大学主办的暑期实习项目中指导选定的学生。