RAPID Proposal: Constraining kinematics of the Whillans/Mercer Ice Stream Confluence

快速提案：Whillans/Mercer 冰流交汇处的约束运动学

• 批准号: 1842021
• 负责人: Seth Campbell
• 金额: $ 4.84万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1842021&HistoricalAwards=false
• 关键词: RAPID; Proposal; Constraining; kinematics; Whillans

The Siple Coast in West Antarctica has undergone significant glacier changes over the last millenium. Several ice streams--rapidly moving streams of ice bordered by slow-moving ice--exist in this region that feeds into the Ross Ice Shelf. A long-term slowdown of Whillans Ice Stream appears to be occurring, and this is affecting the zone between the Whillans and Mercer Ice Streams. However, the consistency of this slowdown and resulting changes to the shear margin between the two ice streams are unknown. The goal of this project is to quantify the observed changes over the past decade and understand the dynamic processes that cause them. A collateral benefit of and driver for this as a RAPID project is to test a method for assessing where crevassing will develop in this zone of steep velocity gradients. Such a method may benefit not only near-term field-project planning in the 2018-19 field season, but also planning for future fieldwork and traverses.The team will use remote sensing feature-tracking techniques to determine transient velocity patterns and shifts in the shear-zone location over the last 10-plus years. This velocity time series will be incorporated into a large-scale ice-sheet model to estimate ice-sheet susceptibility to changing boundary conditions over the next century based on likely regional ice-flux scenarios. This approach is an extension of recent work conducted by the team that shows promise for predicting areas of changing high strain rates indicative of an active glacier shear margin. The ultimate objectives are to characterize the flow field of merging ice streams over time and investigate lateral boundary migration. This will provide a better understanding of shear-margin control on ice-shelf and up-glacier stability.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.

南极西部的Siple海岸在上一个千年中发生了重大冰川变化。几个冰流 - 冰流的冰流被缓慢移动的冰界，在该地区，该地区的冰流进入了罗斯冰架。 Whillans冰流的长期放缓似乎正在发生，这影响了Whillans和Mercer Ice流之间的区域。但是，这两个冰流之间的剪切边缘的变化和导致的变化的一致性尚不清楚。该项目的目的是量化过去十年中观察到的变化，并了解导致它们的动态过程。作为一个快速项目的驱动因素和驱动力的一个快速项目是测试一种用于评估在陡峭速度梯度区域中曲面将在何处发展的方法。 这种方法不仅可以在2018-19实地季节中受益于近期的现场项目计划，还可以计划未来的现场工作和遍历。该团队将使用遥感功能传输技术来确定过去10多年的剪切Zone位置的瞬态速度模式和变化。这个速度时间序列将纳入大型冰盖模型中，以根据可能的区域冰 - 升华场景来估计下一个世纪改变边界条件的冰淇淋敏感性。这种方法是该团队最近进行的工作的扩展，该工作显示了预测更改高应变速率领域的有望，指示了主动冰川剪切边缘。最终目标是表征随着时间的流逝合并冰流的流场并研究横向边界迁移。 这将更好地理解对冰架和上冰台稳定性的剪切剪影控制。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评估标准来通过评估来支持的。