CAREER: Bound to Improve - Improved Estimates of the Glaciological Contribution to Sea Level Rise

这项职业奖支持一个项目，该项目旨在根据未来几个世纪冰盖对海平面上升的影响制定物理界限。为了模拟这些极限，将开发一个三维离散单元模型，并将其应用于模拟格陵兰和南极冰盖上感兴趣的区域。这些地区将包括赫尔海姆冰川、雅各布港Isbräe、松岛冰川和拉森冰架的部分地区。在离散单元模型中，冰将被离散成不同的冰块或冰块，它们通过非弹性碰撞、摩擦力和键作用。最好到最坏情况的频谱将通过改变相邻冰块之间的键的强度和数量来检验。最坏的情况是冰完全断裂，表现得类似于颗粒状材料，而最好的情况是冰完全完整，没有预先存在的缺陷或裂缝。离散单元模型的结果将与类似的连续体模型的结果进行比较，连续体模型将塑性屈服应力纳入更传统的用于模拟冰盖的粘性流动近似中。这样做是为了评估允许塑性流变的断裂是否可以有效地纳入大型冰盖模型，以模拟未来几个世纪冰盖的演变。该奖项还将支持与密歇根州东南部伊普斯兰蒂学区的两位科学教师建立伙伴关系。伊普斯兰蒂学区是一个低收入、资源贫乏的地区，人口中约70%是少数民族，约69%的学生有资格享受免费或减价午餐。拟议的合作伙伴关系的基石是为六年级和七年级的理工科学生制定与动手冰盖动力学活动相关的课程计划和内容。该活动的设计将整合到现有的课堂教学计划中，并与密歇根州科学技术、工程和数学（STEM）课程目标保持一致。该计划的目的不仅是影响小学生，而且还教育教师在研究期间延长伙伴关系的影响。研究生将被指导并参与外展活动，并协助指导本科生。本科生将在开发一个实验模拟冰动力学实验室中发挥关键作用，该实验室旨在说明冰原和冰川是如何流动的，并允许对拟议的研究活动进行实验验证。该研究计划通过基于社区的社区冰盖模型来分发结果，从而推进冰盖建模基础设施。

Bassis/1149085This CAREER award supports a project to develop physically based bounds on the amount ice sheets can contribute to sea level rise in the coming centuries. To simulate these limits, a three-dimensional discrete element model will be developed and applied to simulate regions of interest in the Greenland and Antarctic ice sheets. These regions will include Helheim Glacier, Jakobshavn Isbräe, Pine Island Glacier and sections of the Larsen Ice Shelf. In the discrete element model the ice will be discretized into distinct blocks or boulders of ice that interact through inelastic collisions, frictional forces and bonds. The spectrum of best to worst case scenarios will be examined by varying the strength and number of bonds between neighboring blocks of ice. The worst case scenario corresponds to completely disarticulated ice that behaves in a manner akin to a granular material while the best case scenario corresponds to completely intact ice with no preexisting flaws or fractures. Results from the discrete element model will be compared with those from analogous continuum models that incorporate a plastic yield stress into the more traditional viscous flow approximations used to simulate ice sheets. This will be done to assess if a fracture permitting plastic rheology can be efficiently incorporated into large-scale ice sheet models to simulate the evolution of ice sheets over the coming centuries. This award will also support to forge a partnership with two science teachers in the Ypsilanti school district in southeastern Michigan. The Ypsilanti school district is a low income, resource- poor region with a population that consists of ~70% underrepresented minorities and ~69% of students qualify for a free or reduced cost lunch. The cornerstone of the proposed partnership is the development of lesson plans and content associated with a hands-on ice sheet dynamics activity for 6th and 7th grade science students. The activity will be designed so that it integrates into existing classroom lesson plans and is aligned with State of Michigan Science Technology, Engineering and Math (STEM) curriculum goals. The aim of this program is to not only influence the elementary school students, but also to educate the teachers to extend the impact of the partnership beyond the duration of this study. Graduate students will be mentored and engaged in outreach activities and assist in supervising undergraduate students. Undergraduates will play a key role in developing an experimental, analogue ice dynamics lab designed to illustrate how ice sheets and glaciers flow and allow experimental validation of the proposed research activities. The research program advances ice sheet modeling infrastructure by distributing results through the community based Community Ice Sheet Model.