Collaborative Research: Flow and Fracture Dynamics in an Ice Shelf Lateral Margin: Observations and Modeling of the McMurdo Shear Zone

合作研究：冰架侧缘的流动和断裂动力学：麦克默多剪切带的观测和建模

• 批准号: 1245915
• 负责人: Laura Ray
• 金额: $ 42.5万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1245915&HistoricalAwards=false
• 关键词: Collaborative; Research; Flow; Fracture; Dynamics

Hamilton/1246400This award supports an integrated field observation, remote sensing and numerical modeling study of the McMurdo Shear Zone (SZ). The SZ is a 5-10 km wide strip of heavily crevassed ice that separates the McMurdo and Ross ice shelves, and is an important region of lateral support for the Ross Ice Shelf. Previous radar and remote sensing studies reveal an enigmatic picture of the SZ in which crevasses detected at depth have no apparent surface expression, and have orientations which are possibly inconsistent with the observed flow field. In the proposed work, we seek to test the hypothesis that the SZ is a zone of chaotic Lagrangian mixing with (intersecting) buried crevasses which leads to rheological instability, potentially allowing large scale velocity discontinuities. The work will involve detailed field-based observations of crevasse distributions and structure using ground-penetrating radar, and GPS and remote sensing observations of the flow and stress field in the SZ. Because of the hazardous nature of the SZ, the radar surveys will be conducted largely with the aid of a lightweight robotic vehicle. Observations will be used to develop a finite element model of ice shelf shear margin behavior. The intellectual merit of this project is an increased understanding of ice shelf shear margin dynamics. Shear margins play a key role in ice shelf stability, and ice shelves in turn modulate the flux of ice from the ice sheet across the grounding line to the ocean. Insights from this project will improve large-scale models being developed to predict ice sheet evolution and future rates of sea level rise, which are topics of enormous societal concern. The broader impacts of the project include an improved basis for US Antarctic Program logistics planning as well as numerous opportunities to engage K-12 students in scientific discovery. Intensified crevassing in the shear zone between the Ross and McMurdo ice shelves would preclude surface crossing by heavy traverse vehicles which would lead to increased costs of delivering fuel to South Pole and a concomitant loss of flight time provided by heavy-lift aircraft for science missions on the continent. Our multidisciplinary research combining glaciology, numerical modeling, and robotics engineering is an engaging way to show how robotics can assist scientists in collecting hazardous field measurements. Our outreach activities will leverage Dartmouth's current NSF GK-12 program, build on faculty-educator relationships established during University of Maine's recent GK-12 program, and incorporate project results into University of Maine's IDEAS initiative, which integrates computational modeling with the existing science curriculum at the middle school level. This award has field work in Antarctica.

汉密尔顿/1246400此奖项支持McMurdo剪切区（SZ）的集成现场观察，遥感和数值建模研究。 SZ是一条5-10公里宽的重冰冰条，将McMurdo和Ross Ice架分开，是对Ross Ice架的横向支撑的重要区域。先前的雷达和遥感研究揭示了SZ的神秘图片，其中在深度下检测到的裂缝没有明显的表面表达，并且可能与观察到的流场不一致。在拟议的工作中，我们试图检验以下假设：SZ是混乱的Lagrangian与（相交）埋藏的裂缝的混合区域，这导致了流变学的不稳定，可能允许大规模的速度不连续。这项工作将涉及使用接地雷达的裂隙分布和结构的详细观察结果，而GPS和SZ中流量和应力场的GPS和遥感观察结果。由于SZ的危险性质，雷达调查将主要借助轻型机器人车进行。观察结果将用于开发冰架剪切边缘行为的有限元模型。 该项目的智力优点在于对冰架剪切边缘动态的一种越来越多的了解。剪切边缘在冰架稳定性中起着关键作用，冰架依次调节了从冰盖上的冰块到海洋的冰盖的通量。该项目的见解将改善正在开发的大规模模型，以预测冰盖的演变和未来的海平面上升速度，这是社会关注的巨大关注的主题。 该项目的更广泛影响包括改善美国南极计划物流规划的基础，以及使K-12学生参与科学发现的许多机会。在罗斯和麦克穆尔多冰架之间的剪切区中的裂缝加剧将排除横面的横向交叉，这将导致向南极提供燃料的成本增加，并伴随着由大陆上的科学任务提供的重型飞行时间损失的飞行时间。我们的多学科研究结合了冰川学，数值建模和机器人技术工程是一种引人入胜的方法，以展示机器人如何帮助科学家收集危险的现场测量。我们的外展活动将利用达特茅斯（Dartmouth）当前的NSF GK-12计划，建立在缅因大学最近的GK-12计划期间建立的教师教育者关系，并将项目结果纳入缅因州大学的思想倡议，该计划将计算建模与中学级别的现有科学课程相结合。该奖项在南极洲进行了实地研究。