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: 1246400
• 负责人: Peter Koons
• 金额: $ 32.64万
• 依托单位: University of Maine
• 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 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1246400&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.

Hamilton/1246400该奖项支持麦克默多剪切带（SZ）的综合实地观测、遥感和数值模拟研究。 SZ是一条5-10公里宽的严重裂隙冰带，将麦克默多冰架和罗斯冰架分开，是罗斯冰架横向支撑的重要区域。先前的雷达和遥感研究揭示了 SZ 的神秘图像，其中在深度检测到的裂缝没有明显的表面表现，并且其方向可能与观测到的流场不一致。在拟议的工作中，我们试图检验这样的假设：SZ 是一个混沌拉格朗日混合区，与（相交的）埋藏裂缝混合，导致流变不稳定，可能导致大规模速度不连续。这项工作将包括使用探地雷达对裂缝分布和结构进行详细的现场观测，并对深圳的流动和应力场进行 GPS 和遥感观测。由于 SZ 的危险性，雷达勘测将主要借助轻型机器人车辆进行。观测结果将用于开发冰架剪切裕度行为的有限元模型。 该项目的智力优点是加深了对冰架剪切边缘动力学的了解。剪切边缘在冰架稳定性中起着关键作用，而冰架反过来又调节从冰盖穿过接地线到海洋的冰通量。该项目的见解将改进正在开发的大型模型，以预测冰盖演变和未来海平面上升速度，这些都是社会广泛关注的话题。 该项目的更广泛影响包括改善美国南极计划后勤规划的基础，以及为 K-12 学生参与科学发现提供大量机会。罗斯冰架和麦克默多冰架之间剪切带的裂缝加剧将阻碍重型穿越车辆穿越地表，这将导致向南极运送燃料的成本增加，并随之减少用于执行科学任务的重型飞机提供的飞行时间。大陆。我们的多学科研究结合了冰川学、数值建模和机器人工程，以一种引人入胜的方式展示机器人技术如何帮助科学家收集危险的现场测量结果。我们的外展活动将利用达特茅斯当前的 NSF GK-12 计划，以缅因大学最近的 GK-12 计划期间建立的教师与教育者关系为基础，并将项目成果纳入缅因大学的 IDEAS 计划，该计划将计算建模与现有的科学课程相结合在中学阶段。该奖项在南极洲进行了实地考察。