Evaluation of an emergent feature of sub-shelf melt oscillations from an idealized coupled ice sheet–ocean model using FISOC (v1.1) – ROMSIceShelf (v1.0) – Elmer/Ice (v9.0)
<p>Changes in ocean-driven basal melting have a key influence on the stability of ice shelves, the mass loss from the ice sheet, ocean circulation, and global sea level rise. Coupled ice sheet–ocean models play a critical role in understanding future ice sheet evolution and examining the proce...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-07-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/15/5421/2022/gmd-15-5421-2022.pdf |
| _version_ | 1811291443786940416 |
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| author | C. Zhao R. Gladstone B. K. Galton-Fenzi B. K. Galton-Fenzi B. K. Galton-Fenzi D. Gwyther D. Gwyther T. Hattermann T. Hattermann |
| author_facet | C. Zhao R. Gladstone B. K. Galton-Fenzi B. K. Galton-Fenzi B. K. Galton-Fenzi D. Gwyther D. Gwyther T. Hattermann T. Hattermann |
| author_sort | C. Zhao |
| collection | DOAJ |
| description | <p>Changes in ocean-driven basal melting have a key influence on the stability of ice shelves, the mass loss from the ice sheet, ocean circulation, and global sea level rise. Coupled ice sheet–ocean models play a critical role in understanding future ice sheet evolution and examining the processes governing ice sheet responses to basal melting. However, as a new approach, coupled ice sheet–ocean systems come with new challenges, and the impacts of solutions implemented to date have not been investigated. An emergent feature in several contributing coupled models to the 1st Marine Ice Sheet–Ocean Model Intercomparison Project (MISOMIP1) was a time-varying oscillation in basal melt rates. Here, we use a recently developed coupling framework, FISOC (v1.1), to connect the modified ocean model ROMSIceShelf (v1.0) and ice sheet model Elmer/Ice (v9.0), to investigate the origin and implications of the feature and, more generally, the impact of coupled modeling strategies on the simulated basal melt in an idealized ice shelf cavity based on the MISOMIP setup. We found the spatial-averaged basal melt rates (3.56 m yr<span class="inline-formula"><sup>−1</sup></span>) oscillated with an amplitude <span class="inline-formula">∼0.7</span> m yr<span class="inline-formula"><sup>−1</sup></span> and approximate period of <span class="inline-formula">∼6</span> years between year 30 and 100 depending on the experimental design. The melt oscillations emerged in the coupled system and the standalone ocean model using a prescribed change of cavity geometry. We found that the oscillation feature is closely related to the discretized ungrounding of the ice sheet, exposing new ocean, and is likely strengthened by a combination of positive buoyancy–melt feedback and/or melt–geometry feedback near the grounding line, and the frequent coupling of ice geometry and ocean evolution. Sensitivity tests demonstrate that the oscillation feature is always present, regardless of the choice of coupling interval, vertical resolution in the ocean model, tracer properties of cells ungrounded by the retreating ice sheet, or the dependency of friction velocities to the vertical resolution. However, the amplitude, phase, and sub-cycle variability of the oscillation varied significantly across the different configurations. We were unable to ultimately determine whether the feature arises purely due to numerical issues (related to discretization) or a compounding of multiple physical processes amplifying a numerical artifact. We suggest a pathway and choices of physical parameters to help other efforts understand the coupled ice sheet–ocean system using numerical models.</p> |
| first_indexed | 2024-04-13T04:29:28Z |
| format | Article |
| id | doaj.art-4a1c183d57844f36808317ad6144e0fd |
| institution | Directory Open Access Journal |
| issn | 1991-959X 1991-9603 |
| language | English |
| last_indexed | 2024-04-13T04:29:28Z |
| publishDate | 2022-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Geoscientific Model Development |
| spelling | doaj.art-4a1c183d57844f36808317ad6144e0fd2022-12-22T03:02:22ZengCopernicus PublicationsGeoscientific Model Development1991-959X1991-96032022-07-01155421543910.5194/gmd-15-5421-2022Evaluation of an emergent feature of sub-shelf melt oscillations from an idealized coupled ice sheet–ocean model using FISOC (v1.1) – ROMSIceShelf (v1.0) – Elmer/Ice (v9.0)C. Zhao0R. Gladstone1B. K. Galton-Fenzi2B. K. Galton-Fenzi3B. K. Galton-Fenzi4D. Gwyther5D. Gwyther6T. Hattermann7T. Hattermann8Australian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, AustraliaArctic Centre, University of Lapland, Rovaniemi, FinlandAustralian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, AustraliaAustralian Antarctic Division, Kingston, AustraliaThe Australian Center for Excellence in Antarctic Science, University of Tasmania, Hobart, AustraliaSchool of Mathematics and Physics, The University of Queensland, St Lucia, AustraliaCoastal and Regional Oceanography Lab, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, AustraliaNorwegian Polar Institute, Tromsø, NorwayEnergy and Climate Group, Department of Physics and Technology, The Arctic University – University of Tromsø, Tromsø, Norway<p>Changes in ocean-driven basal melting have a key influence on the stability of ice shelves, the mass loss from the ice sheet, ocean circulation, and global sea level rise. Coupled ice sheet–ocean models play a critical role in understanding future ice sheet evolution and examining the processes governing ice sheet responses to basal melting. However, as a new approach, coupled ice sheet–ocean systems come with new challenges, and the impacts of solutions implemented to date have not been investigated. An emergent feature in several contributing coupled models to the 1st Marine Ice Sheet–Ocean Model Intercomparison Project (MISOMIP1) was a time-varying oscillation in basal melt rates. Here, we use a recently developed coupling framework, FISOC (v1.1), to connect the modified ocean model ROMSIceShelf (v1.0) and ice sheet model Elmer/Ice (v9.0), to investigate the origin and implications of the feature and, more generally, the impact of coupled modeling strategies on the simulated basal melt in an idealized ice shelf cavity based on the MISOMIP setup. We found the spatial-averaged basal melt rates (3.56 m yr<span class="inline-formula"><sup>−1</sup></span>) oscillated with an amplitude <span class="inline-formula">∼0.7</span> m yr<span class="inline-formula"><sup>−1</sup></span> and approximate period of <span class="inline-formula">∼6</span> years between year 30 and 100 depending on the experimental design. The melt oscillations emerged in the coupled system and the standalone ocean model using a prescribed change of cavity geometry. We found that the oscillation feature is closely related to the discretized ungrounding of the ice sheet, exposing new ocean, and is likely strengthened by a combination of positive buoyancy–melt feedback and/or melt–geometry feedback near the grounding line, and the frequent coupling of ice geometry and ocean evolution. Sensitivity tests demonstrate that the oscillation feature is always present, regardless of the choice of coupling interval, vertical resolution in the ocean model, tracer properties of cells ungrounded by the retreating ice sheet, or the dependency of friction velocities to the vertical resolution. However, the amplitude, phase, and sub-cycle variability of the oscillation varied significantly across the different configurations. We were unable to ultimately determine whether the feature arises purely due to numerical issues (related to discretization) or a compounding of multiple physical processes amplifying a numerical artifact. We suggest a pathway and choices of physical parameters to help other efforts understand the coupled ice sheet–ocean system using numerical models.</p>https://gmd.copernicus.org/articles/15/5421/2022/gmd-15-5421-2022.pdf |
| spellingShingle | C. Zhao R. Gladstone B. K. Galton-Fenzi B. K. Galton-Fenzi B. K. Galton-Fenzi D. Gwyther D. Gwyther T. Hattermann T. Hattermann Evaluation of an emergent feature of sub-shelf melt oscillations from an idealized coupled ice sheet–ocean model using FISOC (v1.1) – ROMSIceShelf (v1.0) – Elmer/Ice (v9.0) Geoscientific Model Development |
| title | Evaluation of an emergent feature of sub-shelf melt oscillations from an idealized coupled ice sheet–ocean model using FISOC (v1.1) – ROMSIceShelf (v1.0) – Elmer/Ice (v9.0) |
| title_full | Evaluation of an emergent feature of sub-shelf melt oscillations from an idealized coupled ice sheet–ocean model using FISOC (v1.1) – ROMSIceShelf (v1.0) – Elmer/Ice (v9.0) |
| title_fullStr | Evaluation of an emergent feature of sub-shelf melt oscillations from an idealized coupled ice sheet–ocean model using FISOC (v1.1) – ROMSIceShelf (v1.0) – Elmer/Ice (v9.0) |
| title_full_unstemmed | Evaluation of an emergent feature of sub-shelf melt oscillations from an idealized coupled ice sheet–ocean model using FISOC (v1.1) – ROMSIceShelf (v1.0) – Elmer/Ice (v9.0) |
| title_short | Evaluation of an emergent feature of sub-shelf melt oscillations from an idealized coupled ice sheet–ocean model using FISOC (v1.1) – ROMSIceShelf (v1.0) – Elmer/Ice (v9.0) |
| title_sort | evaluation of an emergent feature of sub shelf melt oscillations from an idealized coupled ice sheet ocean model using fisoc v1 1 romsiceshelf v1 0 elmer ice v9 0 |
| url | https://gmd.copernicus.org/articles/15/5421/2022/gmd-15-5421-2022.pdf |
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