Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources
We analyzed glacier surface elevations (1957, 2010 and 2015) and surface mass-balance measurements (2008–2015) on the 30 km2 Eklutna Glacier, in the Chugach Mountains of southcentral Alaska. The geodetic mass balances from 1957 to 2010 and 2010 to 2015 are −0.52 ± 0.46 and −0.74 ± 0.10 m w.e. a−1, r...
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2017-04-01
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| Series: | Journal of Glaciology |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143016001465/type/journal_article |
| _version_ | 1811155858813353984 |
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| author | LOUIS C. SASS MICHAEL G. LOSO JASON GECK EVAN E. THOMS DANIEL MCGRATH |
| author_facet | LOUIS C. SASS MICHAEL G. LOSO JASON GECK EVAN E. THOMS DANIEL MCGRATH |
| author_sort | LOUIS C. SASS |
| collection | DOAJ |
| description | We analyzed glacier surface elevations (1957, 2010 and 2015) and surface mass-balance measurements (2008–2015) on the 30 km2 Eklutna Glacier, in the Chugach Mountains of southcentral Alaska. The geodetic mass balances from 1957 to 2010 and 2010 to 2015 are −0.52 ± 0.46 and −0.74 ± 0.10 m w.e. a−1, respectively. The glaciological mass balance of −0.73 m w.e. a−1 from 2010 to 2015 is indistinguishable from the geodetic value. Even after accounting for loss of firn in the accumulation zone, we found most of the mass loss over both time periods was from a broad, low-slope basin that includes much of the accumulation zone of the main branch. Ice-equivalent surface elevation changes in the basin were −1.0 ± 0.8 m a−1 from 1957 to 2010, and −0.6 ± 0.1 m a−1 from 2010 to 2015, shifting the glacier hypsometry downward and resulting in more negative mass balances: an altitude-mass-balance feedback. Net mass loss from Eklutna Glacier accounts for 7 ± 1% of the average inflow to Eklutna Reservoir, which is entirely used for water and power by Anchorage, Alaska's largest city. If the altitude-mass-balance feedback continues, this ‘deglaciation discharge dividend’ is likely to increase over the short-term before it eventually decreases due to diminishing glacier area. |
| first_indexed | 2024-04-10T04:41:42Z |
| format | Article |
| id | doaj.art-55c8acbcc9724b4282d17a136f996c27 |
| institution | Directory Open Access Journal |
| issn | 0022-1430 1727-5652 |
| language | English |
| last_indexed | 2024-04-10T04:41:42Z |
| publishDate | 2017-04-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj.art-55c8acbcc9724b4282d17a136f996c272023-03-09T12:40:20ZengCambridge University PressJournal of Glaciology0022-14301727-56522017-04-016334335410.1017/jog.2016.146Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resourcesLOUIS C. SASS0https://orcid.org/0000-0003-4677-029XMICHAEL G. LOSO1JASON GECK2EVAN E. THOMS3DANIEL MCGRATH4Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA Environmental Science, Alaska Pacific University, Anchorage, AK, USAEnvironmental Science, Alaska Pacific University, Anchorage, AK, USA Inventory and Monitoring Program, Wrangell-St. Elias National Park and Preserve, Copper Center, AK, USAEnvironmental Science, Alaska Pacific University, Anchorage, AK, USAAlaska Science Center, U.S. Geological Survey, Anchorage, AK, USAAlaska Science Center, U.S. Geological Survey, Anchorage, AK, USA Geosciences Department, Colorado State University, Fort Collins, CO, USAWe analyzed glacier surface elevations (1957, 2010 and 2015) and surface mass-balance measurements (2008–2015) on the 30 km2 Eklutna Glacier, in the Chugach Mountains of southcentral Alaska. The geodetic mass balances from 1957 to 2010 and 2010 to 2015 are −0.52 ± 0.46 and −0.74 ± 0.10 m w.e. a−1, respectively. The glaciological mass balance of −0.73 m w.e. a−1 from 2010 to 2015 is indistinguishable from the geodetic value. Even after accounting for loss of firn in the accumulation zone, we found most of the mass loss over both time periods was from a broad, low-slope basin that includes much of the accumulation zone of the main branch. Ice-equivalent surface elevation changes in the basin were −1.0 ± 0.8 m a−1 from 1957 to 2010, and −0.6 ± 0.1 m a−1 from 2010 to 2015, shifting the glacier hypsometry downward and resulting in more negative mass balances: an altitude-mass-balance feedback. Net mass loss from Eklutna Glacier accounts for 7 ± 1% of the average inflow to Eklutna Reservoir, which is entirely used for water and power by Anchorage, Alaska's largest city. If the altitude-mass-balance feedback continues, this ‘deglaciation discharge dividend’ is likely to increase over the short-term before it eventually decreases due to diminishing glacier area.https://www.cambridge.org/core/product/identifier/S0022143016001465/type/journal_articleapplied glaciologyclimate changeglacier mass balanceglacier volumemountain glaciers |
| spellingShingle | LOUIS C. SASS MICHAEL G. LOSO JASON GECK EVAN E. THOMS DANIEL MCGRATH Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources Journal of Glaciology applied glaciology climate change glacier mass balance glacier volume mountain glaciers |
| title | Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources |
| title_full | Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources |
| title_fullStr | Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources |
| title_full_unstemmed | Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources |
| title_short | Geometry, mass balance and thinning at Eklutna Glacier, Alaska: an altitude-mass-balance feedback with implications for water resources |
| title_sort | geometry mass balance and thinning at eklutna glacier alaska an altitude mass balance feedback with implications for water resources |
| topic | applied glaciology climate change glacier mass balance glacier volume mountain glaciers |
| url | https://www.cambridge.org/core/product/identifier/S0022143016001465/type/journal_article |
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