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Abstract The time-evolution of glacier basal motion remains poorly constrained, despite its importance in understanding the response of glaciers to climate warming. Athabasca Glacier provides an ideal site for observing changes in basal motion over long timescales. Studies from the 1960s provide an in situ baseline dataset constraining ice deformation and basal motion. We use two complementary numerical flow models to investigate changes along a well-studied transverse profile and throughout a larger study area. A cross-sectional flow model allows us to calculate transverse englacial velocity fields to simulate modern and historical conditions. We subsequently use a 3-D numerical ice flow model, Icepack, to estimate changes in basal friction by inverting known surface velocities. Our results reproduce observed velocities well using standard values for flow parameters. They show that basal motion declined significantly (30–40%) and this constitutes the majority (50–80%) of the observed decrease in surface velocities. At the same time, basal resistive stress has remained nearly constant and now balances a much larger fraction of the driving stress. The decline in basal motion over multiple decades of climate warming could serve as a stabilizing feedback mechanism, slowing ice transport to lower elevations, and therefore moderating future mass loss rates.
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Borehole tiltmeter and water pressure data for Athabasca Glacier, Alberta, Canada (2022-2023)
Research on Athabasca Glacier in the late 1960s constrained ice column deformation rates using borehole inclinometry techniques (Raymond, 1971). This study sought to conduct a field campaign to estimate modern ice deformation rates using an array of 3-axis tiltmeters deployed in Athabasca Glacier. In July 2022, 12 boreholes were drilled to the bed of Athabasca Glacier and instrument strings of three-axis tiltmeters and pressure transducers were deployed at varying depths. The three-axis accelerometers and magnetometer data from these instruments allow for calculation of sensor azimuth and inclination through September 2023. Basal water pressure from sensors with pressure transducers is also reported for this observational period.
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- Award ID(s):
- 1821017
- PAR ID:
- 10638962
- Publisher / Repository:
- NSF Arctic Data Center
- Date Published:
- Subject(s) / Keyword(s):
- Ice Flow Dynamics Tiltmeters Water Pressure Borehole Deformation Cryosphere
- Format(s):
- Medium: X Other: text/xml
- Sponsoring Org:
- National Science Foundation
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