the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 09 Dec 2024
The Impact of Ice Structures and Ocean Warming in Milne Fiord
Abstract. Arctic tidewater glaciers and ice shelves are undergoing rapid attrition, with warmer ocean temperature playing an important role. However, the relationship between ocean temperature and ice structure retreat is complex and may change as the ocean warms and as the ice structure geometry evolves. In order to explore ice-ocean interactions and the impact of retreating ice structures in a glacial fjord, we use a numerical ocean model of Milne Fiord, which features an ice shelf and a tidewater glacier with a floating glacier tongue (part of which is detached). We model past, present and potential future ice configurations. Our results reveal that the average submarine melting is negligible across the ice shelf (<2 cm a-1), but can dominate thinning rates (>20 cm a -1) at specific locations where the ice is thick (>50 m) along the seaward edge. Our simulations also indicate that the temperature of water reaching the grounding line does not vary significantly when the ice shelf and glacier tongue are removed. In addition, we carry out a series of simulations with increasing ocean temperature which reveal a quasi-linear relationship between ocean temperature and submarine melting at the grounding line. Using this relationship and ocean temperature predictions for different greenhouse gas emission scenarios (2020 to 2100), we estimate that Milne Glacier will continue to retreat for at least 50 years, solely in response to ocean forcing. This study highlights the ongoing and future retreat of ice structures in a region considered as the Last Ice Area.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
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Supplement
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(8798 KB) - Metadata XML
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Supplement
(1466 KB) - BibTeX
- EndNote
- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-3651', Anonymous Referee #1, 04 Mar 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3651/egusphere-2024-3651-RC1-supplement.pdf
- AC1: 'Reply on RC1', Jérémie Bonneau, 08 Apr 2025
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RC2: 'Comment on egusphere-2024-3651', Anonymous Referee #2, 12 Mar 2025
This paper investigates recent and anticipated future changes of the distribution of marine glacier ice in Milne Fiord. Using a combination of observations and ocean-circulation modelling, the authors examine how glacier retreat affects subsurface ice melt. The removal of the ice shelf and the ice tongue is found to have only a small impact on the melt at the grounding line of Milne Glacier.
The paper is well structured and written, and should be published after some minor revisions.
Comments
1) It would be useful to connect the present study to work in North Greenland (see e.g., Hill et al., 2017), as similar conditions prevail in this part of the Arctic. The paper cite many studies from Antarctica and Southern Greenland, but Petermann is the only glacier in North Greenland mentioned. In the discussion around L24, it would be relevant to cite Jakobsson et al. (2020) and Nilsson et al. (2023), who investigate the role of sills for blocking inflows of Antarctic Atlantic Water in north Greenlandic fjords. On L70 Thwaites is mentioned, but also C. H. Ostenfeld Glacier in North Greenland has a recently disintegrated ice tonunge (Hill et al., 2017). And Ryder and C. H. Ostenfeld glaciers are situated in fjords that terminate in the perennially sea-covered Lincoln Sea (Hill et al., 2017).
2) Please describe the implementation of the subglacial discharge in the model in section 3.1; this issue is commented on around L355.
3) Check the consistency of the dimensions in Eqs. (5, 6); or state that delta x and delta h are velocities (?)
4) Table 1, 90-220 m Q_{ex}: 2.8ex10^8 -> 2.8x10^8
5) L273: cie shelf -> ice shelf.
References
Hill et al., 2017: A Review of Recent Changes in Major Marine-Terminating Outlet Glaciers in Northern Greenland. doi: 10.3389/feart.2016.00111
Jakobsson et al., 2020: Ryder Glacier in north-west Greenland is shielded from warm Atlantic water by a bathymetric sill. doi: 10.1038/s43247-020-00043-0
Nilsson et al., 2023: Hydraulic suppression of basal glacier melt in sill fjords. doi.org/10.5194/tc-17-2455-2023
Citation: https://doi.org/10.5194/egusphere-2024-3651-RC2 - AC2: 'Reply on RC2', Jérémie Bonneau, 08 Apr 2025
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2024-3651', Anonymous Referee #1, 04 Mar 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3651/egusphere-2024-3651-RC1-supplement.pdf
- AC1: 'Reply on RC1', Jérémie Bonneau, 08 Apr 2025
-
RC2: 'Comment on egusphere-2024-3651', Anonymous Referee #2, 12 Mar 2025
This paper investigates recent and anticipated future changes of the distribution of marine glacier ice in Milne Fiord. Using a combination of observations and ocean-circulation modelling, the authors examine how glacier retreat affects subsurface ice melt. The removal of the ice shelf and the ice tongue is found to have only a small impact on the melt at the grounding line of Milne Glacier.
The paper is well structured and written, and should be published after some minor revisions.
Comments
1) It would be useful to connect the present study to work in North Greenland (see e.g., Hill et al., 2017), as similar conditions prevail in this part of the Arctic. The paper cite many studies from Antarctica and Southern Greenland, but Petermann is the only glacier in North Greenland mentioned. In the discussion around L24, it would be relevant to cite Jakobsson et al. (2020) and Nilsson et al. (2023), who investigate the role of sills for blocking inflows of Antarctic Atlantic Water in north Greenlandic fjords. On L70 Thwaites is mentioned, but also C. H. Ostenfeld Glacier in North Greenland has a recently disintegrated ice tonunge (Hill et al., 2017). And Ryder and C. H. Ostenfeld glaciers are situated in fjords that terminate in the perennially sea-covered Lincoln Sea (Hill et al., 2017).
2) Please describe the implementation of the subglacial discharge in the model in section 3.1; this issue is commented on around L355.
3) Check the consistency of the dimensions in Eqs. (5, 6); or state that delta x and delta h are velocities (?)
4) Table 1, 90-220 m Q_{ex}: 2.8ex10^8 -> 2.8x10^8
5) L273: cie shelf -> ice shelf.
References
Hill et al., 2017: A Review of Recent Changes in Major Marine-Terminating Outlet Glaciers in Northern Greenland. doi: 10.3389/feart.2016.00111
Jakobsson et al., 2020: Ryder Glacier in north-west Greenland is shielded from warm Atlantic water by a bathymetric sill. doi: 10.1038/s43247-020-00043-0
Nilsson et al., 2023: Hydraulic suppression of basal glacier melt in sill fjords. doi.org/10.5194/tc-17-2455-2023
Citation: https://doi.org/10.5194/egusphere-2024-3651-RC2 - AC2: 'Reply on RC2', Jérémie Bonneau, 08 Apr 2025
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Bernard E. Laval
Derek Mueller
Yulia Antropova
Andrew K. Hamilton
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(8798 KB) - Metadata XML
-
Supplement
(1466 KB) - BibTeX
- EndNote
- Final revised paper