Collaborative Research: Disentangling runoff- and Terminus-driven Velocity Variations of Fast Flowing Outlet Glaciers

合作研究：解开快速流动的出口冰川径流和终点驱动的速度变化

• 批准号: 2234730
• 负责人: Jason Amundson
• 金额: $ 15.56万
• 依托单位: University of Alaska Southeast Juneau Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-15 至 2027-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2234730&HistoricalAwards=false
• 关键词: Collaborative; Research; Disentangling; runoff; Terminus

Ice loss from the polar ice sheets is the largest anticipated contribution to global mean-sea-level rise in the coming century. A fundamental control on the rate of ice loss is how fast ice flows from ice sheet interiors out to the edges. In the interior of the Greenland Ice Sheet, ice flow responds to liquid water (“runoff") input, which affects how the ice slides over the bedrock beneath. At ocean-terminating "outlet glaciers” around the edges of Greenland, ice flows into the ocean with speed that varies by season. That strong seasonal variation makes it more difficult to determine the extent to which liquid water input is affecting the flow speed. Identifying the relative strength of ocean-driven versus melt-driven ice flow variations is essential for computer models used to forecast future ice loss. It has been difficult to assess those factors in a consistent way because they operate over multiple time scales, thus requiring different methods of observation that could not be directly compared.This proposal seeks to address three key motivating questions: (Q1) How does runoff affect outlet glacier flow over timescales of hours to years?; (Q2) How does glacier geometry affect the response to runoff?; and (Q3) How do runoff- and terminus-driven velocity variations interact? To address these questions, the PIs will combine new field observations at a large marine-terminating outlet glacier with newly available satellite data from multiple sources, using recently developed methods for flexible time series analysis. Multivariate statistical analysis and idealized numerical model experiments will test hypothesized feedbacks between runoff-driven and terminus-driven changes, as well as connect the observational work to more general settings. The PIs will develop open-source software that allows other researchers to replicate their analysis for remote-sensing and in situ data obtained on any glacier. Museum professionals on the team will coordinate with the PIs to develop a special exhibit on the drivers of Arctic glacier change; after initial installation at the University of Alaska Museum of the North, the exhibit will be made available to tour other Arctic museums.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.

极地冰盖造成的冰损失是未来世纪全球均值上升的最大预期贡献。对冰损失率的基本控制是冰从冰盖内部流向边缘的速度。在格陵兰冰盖的内部，冰流对液​​态水（“径流”）输入的反应，这会影响冰的下面的基岩滑动的方式。在格陵兰岛边缘周围的海洋末端“出口冰川”时，冰以季节变化的速度流入海洋。这种强大的季节性变化使确定液态水输入影响流速的程度变得更加困难。确定海洋驱动与熔体驱动的冰流变化的相对强度对于用于预测未来冰损失的计算机模型至关重要。很难以一致的方式评估这些因素，因为它们在多个时间尺度上运行，因此需要无法直接比较的不同观察方法。该提案试图解决三个关键的动机问题：（Q1）径流如何影响径流冰川流量在数年的小时时间内散发出冰川流量？ （Q2）冰川几何形状如何影响对径流的反应？ （Q3）径流和末端驱动的速度变化如何相互作用？为了解决这些问题，PI将使用最近开发的用于灵活的时间序列分析的方法将新的现场观测与来自多个来源的新可用卫星数据相结合。多元统计分析和理想化的数值模型实验将测试径流驱动和末端驱动的变化之间的假设反馈，并将观察工作连接到更一般的环境。 PI将开发开源软件，使其他研究人员能够复制其分析，以进行遥感和在任何冰川上获得的原位数据。团队中的博物馆专业人士将与PIS协调，以开发有关北极冰川变化司机的特别展览；在北部阿拉斯加大学博物馆进行了最初的安装后，该展览将用于参观其他北极博物馆。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响审查标准来评估，被认为是珍贵的支持。