CAREER: Fracture Mechanics of Antarctic Ice Shelves and Glaciers - Representing Iceberg Calving in Ice Sheet Models and Developing Cyberlearning Tools for Outreach

冰山崩解是一个复杂的自然断裂过程，也是南极冰盖边缘浮冰架质量损失的主要原因。人们担心，这些冰架的快速变化可能会破坏冰盖部分的稳定，并加速它们对海平面上升的贡献。 这个项目的目标是了解和模拟断裂力学的冰解，并制定物理一致的冰解计划冰盖模型。 这将减少预测的不确定性，从而能够更可靠地估计南极质量损失。 该研究计划与教育和推广计划相结合，旨在（1）通过跨学院课程和高性能计算研讨会提高工程和地球科学学生的计算建模技能，（2）通过为本科生提供跨学科研究机会，并通过部署新的网络学习工具来吸引当地知识分子，提高工程和科学的参与度和多样性。12名学生在纳什维尔大都会公立学校学习计算科学和工程以及冰川学。该项目旨在通过推进计算断裂力学和非线性连续介质力学的前沿并将其转化为冰川学来提供对冰山崩解的基本理解。 该项目研究裂缝传播使用孔隙损伤力学模型水力压裂是一致的非线性粘性冰流变学，沿着在狭窄的裂缝在米长尺度的再冻结热力学。它将开发一个基于冰物理学的方案，以便使用多尺度方法更好地表示冰盖模型中的产犊。该努力还将解决与浮冰架和冰川崩解行为相关的研究问题，目标是在整个南极冰盖模拟中，在十年到千年的时间尺度上对崩解锋进行更可靠的预测。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Iceberg calving is a complex natural fracture process and a dominant cause of mass loss from the floating ice shelves on the margins of the Antarctic ice sheet. There is concern that rapid changes at these ice shelves can destabilize parts of the ice sheet and accelerate their contribution to sea-level rise. The goal of this project is to understand and simulate the fracture mechanics of calving and to develop physically-consistent calving schemes for ice-sheet models. This would enable more reliable estimation of Antarctic mass loss by reducing the uncertainty in projections. The research plan is integrated with an education and outreach plan that aims to (1) enhance computational modeling skills of engineering and Earth science students through a cross-college course and a high-performance computing workshop and (2) increase participation and diversity in engineering and sciences by providing interdisciplinary research opportunities to undergraduates and by deploying new cyberlearning tools to engage local K-12 students in the Metro Nashville Public Schools in computational science and engineering, and glaciology.This project aims to provide fundamental understanding of iceberg calving by advancing the frontiers in computational fracture mechanics and nonlinear continuum mechanics and translating it to glaciology. The project investigates crevasse propagation using poro-damage mechanics models for hydrofracture that are consistent with nonlinear viscous ice rheology, along with the thermodynamics of refreezing in narrow crevasses at meter length scales. It will develop a fracture-physics based scheme to better represent calving in ice-sheet models using a multiscale method. The effort will also address research questions related to calving behavior of floating ice shelves and glaciers, with the goal of enabling more reliable prediction of calving fronts in whole-Antarctic ice-sheet simulations over decadal-to-millennial time scales.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.