Near‐glacier surveying of a subglacial discharge plume: Implications for plume parameterizations
Abstract At tidewater glaciers, plume dynamics affect submarine melting, fjord circulation, and the mixing of meltwater. Models often rely on buoyant plume theory to parameterize plumes and submarine melting; however, these parameterizations are largely untested due to a dearth of near‐glacier measu...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2017-07-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1002/2017GL073602 |
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| author | R. H. Jackson E. L. Shroyer J. D. Nash D. A. Sutherland D. Carroll M. J. Fried G. A. Catania T. C. Bartholomaus L. A. Stearns |
| author_facet | R. H. Jackson E. L. Shroyer J. D. Nash D. A. Sutherland D. Carroll M. J. Fried G. A. Catania T. C. Bartholomaus L. A. Stearns |
| author_sort | R. H. Jackson |
| collection | DOAJ |
| description | Abstract At tidewater glaciers, plume dynamics affect submarine melting, fjord circulation, and the mixing of meltwater. Models often rely on buoyant plume theory to parameterize plumes and submarine melting; however, these parameterizations are largely untested due to a dearth of near‐glacier measurements. Here we present a high‐resolution ocean survey by ship and remotely operated boat near the terminus of Kangerlussuup Sermia in west Greenland. These novel observations reveal the 3‐D structure and transport of a near‐surface plume, originating at a large undercut conduit in the glacier terminus, that is inconsistent with axisymmetric plume theory, the most common representation of plumes in ocean‐glacier models. Instead, the observations suggest a wider upwelling plume—a “truncated” line plume of ∼200 m width—with higher entrainment and plume‐driven melt compared to the typical axisymmetric representation. Our results highlight the importance of a subglacial outlet's geometry in controlling plume dynamics, with implications for parameterizing the exchange flow and submarine melt in glacial fjord models. |
| format | Article |
| id | doaj-art-a60c150933e1467a9ef36b54c29f7ba6 |
| institution | DOAJ |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2017-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-a60c150933e1467a9ef36b54c29f7ba62025-08-20T03:10:28ZengWileyGeophysical Research Letters0094-82761944-80072017-07-0144136886689410.1002/2017GL073602Near‐glacier surveying of a subglacial discharge plume: Implications for plume parameterizationsR. H. Jackson0E. L. Shroyer1J. D. Nash2D. A. Sutherland3D. Carroll4M. J. Fried5G. A. Catania6T. C. Bartholomaus7L. A. Stearns8College of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis Oregon USACollege of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis Oregon USACollege of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis Oregon USADepartment of Earth Sciences University of Oregon Eugene Oregon USADepartment of Earth Sciences University of Oregon Eugene Oregon USAInstitute for Geophysics University of Texas at Austin Austin Texas USAInstitute for Geophysics University of Texas at Austin Austin Texas USADepartment of Geography University of Idaho Moscow Idaho USADepartment of Geology University of Kansas Lawrence Kansas USAAbstract At tidewater glaciers, plume dynamics affect submarine melting, fjord circulation, and the mixing of meltwater. Models often rely on buoyant plume theory to parameterize plumes and submarine melting; however, these parameterizations are largely untested due to a dearth of near‐glacier measurements. Here we present a high‐resolution ocean survey by ship and remotely operated boat near the terminus of Kangerlussuup Sermia in west Greenland. These novel observations reveal the 3‐D structure and transport of a near‐surface plume, originating at a large undercut conduit in the glacier terminus, that is inconsistent with axisymmetric plume theory, the most common representation of plumes in ocean‐glacier models. Instead, the observations suggest a wider upwelling plume—a “truncated” line plume of ∼200 m width—with higher entrainment and plume‐driven melt compared to the typical axisymmetric representation. Our results highlight the importance of a subglacial outlet's geometry in controlling plume dynamics, with implications for parameterizing the exchange flow and submarine melt in glacial fjord models.https://doi.org/10.1002/2017GL073602plumefjordglacierentrainmentsubmarine meltsubglacial discharge |
| spellingShingle | R. H. Jackson E. L. Shroyer J. D. Nash D. A. Sutherland D. Carroll M. J. Fried G. A. Catania T. C. Bartholomaus L. A. Stearns Near‐glacier surveying of a subglacial discharge plume: Implications for plume parameterizations Geophysical Research Letters plume fjord glacier entrainment submarine melt subglacial discharge |
| title | Near‐glacier surveying of a subglacial discharge plume: Implications for plume parameterizations |
| title_full | Near‐glacier surveying of a subglacial discharge plume: Implications for plume parameterizations |
| title_fullStr | Near‐glacier surveying of a subglacial discharge plume: Implications for plume parameterizations |
| title_full_unstemmed | Near‐glacier surveying of a subglacial discharge plume: Implications for plume parameterizations |
| title_short | Near‐glacier surveying of a subglacial discharge plume: Implications for plume parameterizations |
| title_sort | near glacier surveying of a subglacial discharge plume implications for plume parameterizations |
| topic | plume fjord glacier entrainment submarine melt subglacial discharge |
| url | https://doi.org/10.1002/2017GL073602 |
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