Modeling the response of northwest Greenland to enhanced ocean thermal forcing and subglacial discharge
<p>Calving-front dynamics is an important control on Greenland's ice mass balance. Ice front retreat of marine-terminating glaciers may, for example, lead to a loss in resistive stress, which ultimately results in glacier acceleration and thinning. Over the past decade, it has been sugges...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-03-01
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| Series: | The Cryosphere |
| Online Access: | https://www.the-cryosphere.net/13/723/2019/tc-13-723-2019.pdf |
| _version_ | 1798043646461739008 |
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| author | M. Morlighem M. Morlighem M. Wood H. Seroussi Y. Choi E. Rignot E. Rignot |
| author_facet | M. Morlighem M. Morlighem M. Wood H. Seroussi Y. Choi E. Rignot E. Rignot |
| author_sort | M. Morlighem |
| collection | DOAJ |
| description | <p>Calving-front dynamics is an important
control on Greenland's ice mass balance. Ice front retreat of
marine-terminating glaciers may, for example, lead to a loss in resistive
stress, which ultimately results in glacier acceleration and thinning. Over
the past decade, it has been suggested that such retreats may be triggered by
warm and salty Atlantic Water, which is typically found at a depth below
200–300 m. An increase in subglacial water discharge at glacier ice fronts
due to enhanced surface runoff may also be responsible for an intensification
of undercutting and calving. An increase in ocean thermal forcing or
subglacial discharge therefore has the potential to destabilize
marine-terminating glaciers along the coast of Greenland. It remains unclear
which glaciers are currently stable but may retreat in the future and how far
inland and how fast they will retreat. Here, we quantify the sensitivity and
vulnerability of marine-terminating glaciers along the northwest coast of
Greenland (from 72.5 to 76<span class="inline-formula"><sup>∘</sup></span> N) to ocean forcing and subglacial
discharge using the Ice Sheet System Model (ISSM). We rely on a
parameterization of undercutting based on ocean thermal forcing and
subglacial discharge and use ocean temperature and salinity from
high-resolution ECCO2 (Estimating the Circulation and Climate of the Ocean,
Phase II) simulations at the fjord mouth to constrain the ocean thermal
forcing. The ice flow model includes a calving law based on a tensile von
Mises criterion. We find that some glaciers, such as Dietrichson Gletscher or
Alison Glacier, are sensitive to small increases in ocean thermal forcing,
while others, such as Illullip Sermia or Cornell
Gletscher, are remarkably stable,
even in a <span class="inline-formula">+3</span> <span class="inline-formula"><sup>∘</sup></span>C ocean warming scenario. Under the most intense
experiment, we find that Hayes Gletscher retreats by more than 50 km inland by 2100 into a deep trough,
and its velocity increases by a factor of 3 over only 23 years. The model
confirms that ice–ocean interactions can trigger extensive and rapid glacier
retreat, but the bed controls the rate and magnitude of the retreat. Under
current oceanic and atmospheric conditions, we find that this sector of the
Greenland ice sheet alone will contribute more than 1 cm to sea level rise
and up to 3 cm by 2100 under the most extreme scenario.</p> |
| first_indexed | 2024-04-11T22:51:58Z |
| format | Article |
| id | doaj.art-9b66c0fc80d54fa791bcda2c3b459090 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-04-11T22:51:58Z |
| publishDate | 2019-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-9b66c0fc80d54fa791bcda2c3b4590902022-12-22T03:58:34ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242019-03-011372373410.5194/tc-13-723-2019Modeling the response of northwest Greenland to enhanced ocean thermal forcing and subglacial dischargeM. Morlighem0M. Morlighem1M. Wood2H. Seroussi3Y. Choi4E. Rignot5E. Rignot6Department of Earth System Science, University of California, Irvine, 3218 Croul Hall, Irvine, CA 92697-3100, USA Invited contribution by Mathieu Morlighem, recipient of the EGU Arne Richter Award for Outstanding Early Career Scientists 2018. Department of Earth System Science, University of California, Irvine, 3218 Croul Hall, Irvine, CA 92697-3100, USAJet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USADepartment of Earth System Science, University of California, Irvine, 3218 Croul Hall, Irvine, CA 92697-3100, USADepartment of Earth System Science, University of California, Irvine, 3218 Croul Hall, Irvine, CA 92697-3100, USAJet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA<p>Calving-front dynamics is an important control on Greenland's ice mass balance. Ice front retreat of marine-terminating glaciers may, for example, lead to a loss in resistive stress, which ultimately results in glacier acceleration and thinning. Over the past decade, it has been suggested that such retreats may be triggered by warm and salty Atlantic Water, which is typically found at a depth below 200–300 m. An increase in subglacial water discharge at glacier ice fronts due to enhanced surface runoff may also be responsible for an intensification of undercutting and calving. An increase in ocean thermal forcing or subglacial discharge therefore has the potential to destabilize marine-terminating glaciers along the coast of Greenland. It remains unclear which glaciers are currently stable but may retreat in the future and how far inland and how fast they will retreat. Here, we quantify the sensitivity and vulnerability of marine-terminating glaciers along the northwest coast of Greenland (from 72.5 to 76<span class="inline-formula"><sup>∘</sup></span> N) to ocean forcing and subglacial discharge using the Ice Sheet System Model (ISSM). We rely on a parameterization of undercutting based on ocean thermal forcing and subglacial discharge and use ocean temperature and salinity from high-resolution ECCO2 (Estimating the Circulation and Climate of the Ocean, Phase II) simulations at the fjord mouth to constrain the ocean thermal forcing. The ice flow model includes a calving law based on a tensile von Mises criterion. We find that some glaciers, such as Dietrichson Gletscher or Alison Glacier, are sensitive to small increases in ocean thermal forcing, while others, such as Illullip Sermia or Cornell Gletscher, are remarkably stable, even in a <span class="inline-formula">+3</span> <span class="inline-formula"><sup>∘</sup></span>C ocean warming scenario. Under the most intense experiment, we find that Hayes Gletscher retreats by more than 50 km inland by 2100 into a deep trough, and its velocity increases by a factor of 3 over only 23 years. The model confirms that ice–ocean interactions can trigger extensive and rapid glacier retreat, but the bed controls the rate and magnitude of the retreat. Under current oceanic and atmospheric conditions, we find that this sector of the Greenland ice sheet alone will contribute more than 1 cm to sea level rise and up to 3 cm by 2100 under the most extreme scenario.</p>https://www.the-cryosphere.net/13/723/2019/tc-13-723-2019.pdf |
| spellingShingle | M. Morlighem M. Morlighem M. Wood H. Seroussi Y. Choi E. Rignot E. Rignot Modeling the response of northwest Greenland to enhanced ocean thermal forcing and subglacial discharge The Cryosphere |
| title | Modeling the response of northwest Greenland to enhanced ocean thermal forcing and subglacial discharge |
| title_full | Modeling the response of northwest Greenland to enhanced ocean thermal forcing and subglacial discharge |
| title_fullStr | Modeling the response of northwest Greenland to enhanced ocean thermal forcing and subglacial discharge |
| title_full_unstemmed | Modeling the response of northwest Greenland to enhanced ocean thermal forcing and subglacial discharge |
| title_short | Modeling the response of northwest Greenland to enhanced ocean thermal forcing and subglacial discharge |
| title_sort | modeling the response of northwest greenland to enhanced ocean thermal forcing and subglacial discharge |
| url | https://www.the-cryosphere.net/13/723/2019/tc-13-723-2019.pdf |
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