Investigating the boundaries of glaciology

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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.