Short-term velocity variations and sliding sensitivity of a slowly surging glacier
We use daily surface velocities measured over several weeks in 2007 and 2008 on a slowly surging glacier in Yukon, Canada, to examine the ordinary melt-season dynamics in the context of the ongoing surge. Horizontal velocities within and just below the ~1.5 km-long zone of fastest flow, where the su...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2016-07-01
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| Series: | Annals of Glaciology |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0260305516000070/type/journal_article |
| _version_ | 1811157329774641152 |
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| author | Gwenn E. Flowers Alexander H. Jarosch Patrick T. A. P. Belliveau Lucas A. Fuhrman |
| author_facet | Gwenn E. Flowers Alexander H. Jarosch Patrick T. A. P. Belliveau Lucas A. Fuhrman |
| author_sort | Gwenn E. Flowers |
| collection | DOAJ |
| description | We use daily surface velocities measured over several weeks in 2007 and 2008 on a slowly surging glacier in Yukon, Canada, to examine the ordinary melt-season dynamics in the context of the ongoing surge. Horizontal velocities within and just below the ~1.5 km-long zone of fastest flow, where the surge is occurring, are often correlated during intervals of low melt. This correlation breaks down during melt events, with the lower reaches of the fast-flow zone responding first. Velocity variability in this lower reach is most highly correlated with melt; velocities above and below appear to respond at least as strongly to the velocity variations of this reach as to local melt. GPS height records are suggestive of ice/bed separation occurring in the fast-flow zone but not below it, pointing to a hydrological cause for the short-term flow variability in the surging region. Independent velocity measurements over 6 years show a maximum July flow anomaly coincident with the location most responsive to melt. Results from a simple model of dashpots and frictional elements lend support to the hypothesis that this zone partly drives the dynamics of the ice above and below it. We speculate that the slow surge may enhance glacier sensitivity to melt-season processes, including short-term summer sliding events. |
| first_indexed | 2024-04-10T05:04:23Z |
| format | Article |
| id | doaj.art-0b9b7301ad784ff2b92933e85509cb9d |
| institution | Directory Open Access Journal |
| issn | 0260-3055 1727-5644 |
| language | English |
| last_indexed | 2024-04-10T05:04:23Z |
| publishDate | 2016-07-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Annals of Glaciology |
| spelling | doaj.art-0b9b7301ad784ff2b92933e85509cb9d2023-03-09T12:27:29ZengCambridge University PressAnnals of Glaciology0260-30551727-56442016-07-0157718310.1017/aog.2016.7Short-term velocity variations and sliding sensitivity of a slowly surging glacierGwenn E. Flowers0Alexander H. Jarosch1Patrick T. A. P. Belliveau2Lucas A. Fuhrman3Department of Earth Sciences, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada E-mail:Institute of Earth Sciences, University of Iceland, Sturlugata 7, Reykjavík, IcelandDepartment of Earth Sciences, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada E-mail:Department of Earth Sciences, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada E-mail:We use daily surface velocities measured over several weeks in 2007 and 2008 on a slowly surging glacier in Yukon, Canada, to examine the ordinary melt-season dynamics in the context of the ongoing surge. Horizontal velocities within and just below the ~1.5 km-long zone of fastest flow, where the surge is occurring, are often correlated during intervals of low melt. This correlation breaks down during melt events, with the lower reaches of the fast-flow zone responding first. Velocity variability in this lower reach is most highly correlated with melt; velocities above and below appear to respond at least as strongly to the velocity variations of this reach as to local melt. GPS height records are suggestive of ice/bed separation occurring in the fast-flow zone but not below it, pointing to a hydrological cause for the short-term flow variability in the surging region. Independent velocity measurements over 6 years show a maximum July flow anomaly coincident with the location most responsive to melt. Results from a simple model of dashpots and frictional elements lend support to the hypothesis that this zone partly drives the dynamics of the ice above and below it. We speculate that the slow surge may enhance glacier sensitivity to melt-season processes, including short-term summer sliding events.https://www.cambridge.org/core/product/identifier/S0260305516000070/type/journal_articleglacier flowglacier mechanicsglacier surgesmountain glacierssubglacial processes |
| spellingShingle | Gwenn E. Flowers Alexander H. Jarosch Patrick T. A. P. Belliveau Lucas A. Fuhrman Short-term velocity variations and sliding sensitivity of a slowly surging glacier Annals of Glaciology glacier flow glacier mechanics glacier surges mountain glaciers subglacial processes |
| title | Short-term velocity variations and sliding sensitivity of a slowly surging glacier |
| title_full | Short-term velocity variations and sliding sensitivity of a slowly surging glacier |
| title_fullStr | Short-term velocity variations and sliding sensitivity of a slowly surging glacier |
| title_full_unstemmed | Short-term velocity variations and sliding sensitivity of a slowly surging glacier |
| title_short | Short-term velocity variations and sliding sensitivity of a slowly surging glacier |
| title_sort | short term velocity variations and sliding sensitivity of a slowly surging glacier |
| topic | glacier flow glacier mechanics glacier surges mountain glaciers subglacial processes |
| url | https://www.cambridge.org/core/product/identifier/S0260305516000070/type/journal_article |
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