Investigating the boundaries of glaciology

地球的冰川和冰盖构成了决定未来海平面上升的最重要变量。最容易迅速变化的冰川是南极洲、格陵兰岛和北极部分地区与海洋相互作用的大型冰流。控制这些冰流迅速流失的过程主要在它们的边界上运行，包括在冰-海洋界面和定义冰流边缘的剪切边缘。这些动态过程已经通过数值模型进行了观测和预测，但仍然知之甚少，部分原因是缺乏观测数据。拟议的研究方案力求通过对遥感和实地数据的分析，促进对这些过程的了解。目标是：1.确定和了解导致冰架坍塌的机制；2.量化海洋热传输、沟道化流动、冰流和冰流基准线上的冰川崩解之间的相互作用；3.调查影响目标1和2中所调查的冰-海洋边界的剪切边缘过程。这项跨学科工作与当前的环境问题有关，需要使用灵活的量化工具，并强调外联和交流，使其非常适合在所有学术级别培训总部质量保证计划。南极工作将使用光学图像、激光测高和数字海拔模型来调查冰架过程。这项工作将通过与国际Thwaites冰川合作其他成员的密切合作来促进，这将使其能够与机载和地面雷达数据进行比较。在南极洲取得的成果将扩展到格陵兰岛，在那里的工作将侧重于接地线和剪切边缘过程，在格陵兰西部的UperNavik Isstrom进行实地工作，这是Dorthe Dahl-Jensen博士关于巴芬湾海洋-淡水耦合的加拿大卓越研究教席(CERC)的重点地点。格陵兰岛的分析将包括遥感数据，还将利用海洋和冰上仪器来检查冰锋的融化和崩解模式。我的发现计划中提出的工作将通过增加对埃尔斯米尔岛上的Sydkap冰川的关注，为CERC项目增加一个额外的维度。我的团队将利用在格陵兰岛获得的经验，与渥太华大学Luke Copland博士的团队合作，对Sydkap冰川及其前面的冰-海洋相互作用进行比较研究。从长远来看，这些互补性研究将允许比较不同冰川几何形状、退缩阶段和海洋压力的相似过程，这将使确定与冰川环境相关的基本模式和过程成为可能。这些研究产生的观测数据和改进的过程理解将为预测未来海平面上升所需的数值模型提供依据。由于加拿大拥有比其他任何国家都多的海岸线，这些都是需要理解的重要问题。

Earth's glaciers and ice sheets comprise the most important variable in determining future sea-level rise. The glaciers that are most prone to rapid change are large ice streams in Antarctica, Greenland, and parts of the Arctic that interact with the ocean. Processes that govern the rapid loss of these ice streams operate largely at their boundaries, including at ice-ocean interfaces and the shear margins that define ice-stream edges. These dynamic processes have been observed and predicted by numerical models, but are still poorly understood, due in part to a lack of observational data. The proposed research program seeks to contribute to understanding of these processes through the analysis of remote sensing and field data. The objectives are to: 1. Identify and understand mechanisms that lead to ice-shelf collapse, 2. Quantify the interactions between ocean heat transport, channelized flow, and calving at ice-stream grounding lines, and 3. Investigate the shear-margin processes that influence the ice-ocean boundaries investigated in objectives 1 and 2. This interdisciplinary work is relevant to current environment issues, requires the use of flexible quantitative tools, and emphasizes outreach and communication, making it highly suitable for training HQP at all academic levels. Antarctic work will investigate ice-shelf processes using optical imagery, laser altimetry, and digital elevation models. This work will be facilitated by close collaboration with fellow members of the International Thwaites Glacier Collaboration, which will allow for comparison with airborne and ground-based radar data. Results in Antarctica will be extended to Greenland, where work will focus on grounding-line and shear-margin processes, with fieldwork on Upernavik Isstrom in western Greenland, a focus site in Dr. Dorthe Dahl-Jensen's Canada Excellence Research Chair (CERC) on marine-freshwater coupling in Baffin Bay. The Greenland analysis will include remote sensing data and also utilize ocean and on-ice instrumentation to examine melting and calving patterns at ice fronts. Work proposed in my Discovery program will add an extra dimension to the CERC project by adding a focus on Sydkap Glacier on Ellesmere Island. My group will use the experience gained in Greenland to carry out comparative studies of ice-ocean interaction on and in front of Sydkap Glacier, in collaboration with Dr. Luke Copland's group at the University of Ottawa. In the long-term, these complementary studies will allow for comparison of similar processes across varied glacier geometries, stages of retreat, and ocean forcing, which will make it possible to identify fundamental patterns and processes relevant across glaciological settings. The observational data and improved process understanding yielded by these studies will inform numerical models, which are needed to predict future sea-level rise. As Canada has more coastline than any other country, these are vital issues to understand.