Reduced basal motion responsible for 50 years of declining ice velocities on Athabasca Glacier
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 b...
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Cambridge University Press
2024-01-01
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| Series: | Journal of Glaciology |
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| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143024000510/type/journal_article |
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| author | David Polashenski Martin Truffer William Henry Armstrong |
| author_facet | David Polashenski Martin Truffer William Henry Armstrong |
| author_sort | David Polashenski |
| collection | DOAJ |
| description | 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. |
| format | Article |
| id | doaj-art-55dd50da4c7f4cb4a30ce87efea5dacc |
| institution | DOAJ |
| issn | 0022-1430 1727-5652 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj-art-55dd50da4c7f4cb4a30ce87efea5dacc2025-08-20T02:41:21ZengCambridge University PressJournal of Glaciology0022-14301727-56522024-01-017010.1017/jog.2024.51Reduced basal motion responsible for 50 years of declining ice velocities on Athabasca GlacierDavid Polashenski0https://orcid.org/0000-0002-4641-1898Martin Truffer1https://orcid.org/0000-0001-8251-7043William Henry Armstrong2https://orcid.org/0000-0002-5581-6109University of Alaska Fairbanks, Fairbanks, AK, USAUniversity of Alaska Fairbanks, Fairbanks, AK, USAAppalachian State University, Boone, NC, USAThe 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.https://www.cambridge.org/core/product/identifier/S0022143024000510/type/journal_articleglacier flowglacier modelingmountain glaciers |
| spellingShingle | David Polashenski Martin Truffer William Henry Armstrong Reduced basal motion responsible for 50 years of declining ice velocities on Athabasca Glacier Journal of Glaciology glacier flow glacier modeling mountain glaciers |
| title | Reduced basal motion responsible for 50 years of declining ice velocities on Athabasca Glacier |
| title_full | Reduced basal motion responsible for 50 years of declining ice velocities on Athabasca Glacier |
| title_fullStr | Reduced basal motion responsible for 50 years of declining ice velocities on Athabasca Glacier |
| title_full_unstemmed | Reduced basal motion responsible for 50 years of declining ice velocities on Athabasca Glacier |
| title_short | Reduced basal motion responsible for 50 years of declining ice velocities on Athabasca Glacier |
| title_sort | reduced basal motion responsible for 50 years of declining ice velocities on athabasca glacier |
| topic | glacier flow glacier modeling mountain glaciers |
| url | https://www.cambridge.org/core/product/identifier/S0022143024000510/type/journal_article |
| work_keys_str_mv | AT davidpolashenski reducedbasalmotionresponsiblefor50yearsofdecliningicevelocitiesonathabascaglacier AT martintruffer reducedbasalmotionresponsiblefor50yearsofdecliningicevelocitiesonathabascaglacier AT williamhenryarmstrong reducedbasalmotionresponsiblefor50yearsofdecliningicevelocitiesonathabascaglacier |