Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current
Efforts to parameterize ice shelf basal melting within climate models are limited by an incomplete understanding of the influence of ice base slope on the turbulent ice shelf–ocean boundary current (ISOBC). Here, we examine the relationship between ice base slope, boundary current dynamics, and melt...
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American Meteorological Society
2024
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ftnerc:oai:nora.nerc.ac.uk:536538 2024-09-15T17:43:22+00:00 Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current Anselin, J. Holland, P.R. Jenkins, A. Taylor, J.R. 2024-07-01 text http://nora.nerc.ac.uk/id/eprint/536538/ https://nora.nerc.ac.uk/id/eprint/536538/1/phoc-JPO-D-23-0256.1.pdf https://journals.ametsoc.org/view/journals/phoc/54/7/JPO-D-23-0256.1.xml en eng American Meteorological Society https://nora.nerc.ac.uk/id/eprint/536538/1/phoc-JPO-D-23-0256.1.pdf Anselin, J. orcid:0000-0003-4057-3869 Holland, P.R. orcid:0000-0001-8370-289X Jenkins, A.; Taylor, J.R. 2024 Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current. Journal of Physical Oceanography, 54 (7). 1545-1562. https://doi.org/10.1175/JPO-D-23-0256.1 <https://doi.org/10.1175/JPO-D-23-0256.1> cc_by_4 Publication - Article PeerReviewed 2024 ftnerc https://doi.org/10.1175/JPO-D-23-0256.1 2024-08-13T23:39:30Z Efforts to parameterize ice shelf basal melting within climate models are limited by an incomplete understanding of the influence of ice base slope on the turbulent ice shelf–ocean boundary current (ISOBC). Here, we examine the relationship between ice base slope, boundary current dynamics, and melt rate using 3D, turbulence-permitting large-eddy simulations (LESs) of an idealized ice shelf–ocean boundary current forced solely by melt-induced buoyancy. The range of simulated slopes (3%–10%) is appropriate to the grounding zone of small Antarctic ice shelves and to the flanks of relatively wide ice base channels, and the initial conditions are representative of warm-cavity ocean conditions. In line with previous studies, the simulations feature the development of an Ekman boundary layer adjacent to the ice, overlaying a broad pycnocline. The time-averaged flow within the pycnocline is in thermal wind balance, with a mean shear that is only weakly dependent on the ice base slope angle α, resulting in a mean gradient Richardson number 〈Ri g 〉 that decreases approximately linearly with sinα. Combining this inverse relationship with a linear approximation to the density profile, we derive formulations for the friction velocity, thermal forcing, and melt rate in terms of slope angle and total buoyancy input. This theory predicts that melt rate varies like the square root of slope, which is consistent with the LES results and differs from a previously proposed linear trend. The derived scalings provide a potential framework for incorporating slope dependence into parameterizations of mixing and melting at the base of ice shelves. Article in Journal/Newspaper Antarc* Antarctic Ice Shelf Ice Shelves Natural Environment Research Council: NERC Open Research Archive Journal of Physical Oceanography 54 7 1545 1562 |
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Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Efforts to parameterize ice shelf basal melting within climate models are limited by an incomplete understanding of the influence of ice base slope on the turbulent ice shelf–ocean boundary current (ISOBC). Here, we examine the relationship between ice base slope, boundary current dynamics, and melt rate using 3D, turbulence-permitting large-eddy simulations (LESs) of an idealized ice shelf–ocean boundary current forced solely by melt-induced buoyancy. The range of simulated slopes (3%–10%) is appropriate to the grounding zone of small Antarctic ice shelves and to the flanks of relatively wide ice base channels, and the initial conditions are representative of warm-cavity ocean conditions. In line with previous studies, the simulations feature the development of an Ekman boundary layer adjacent to the ice, overlaying a broad pycnocline. The time-averaged flow within the pycnocline is in thermal wind balance, with a mean shear that is only weakly dependent on the ice base slope angle α, resulting in a mean gradient Richardson number 〈Ri g 〉 that decreases approximately linearly with sinα. Combining this inverse relationship with a linear approximation to the density profile, we derive formulations for the friction velocity, thermal forcing, and melt rate in terms of slope angle and total buoyancy input. This theory predicts that melt rate varies like the square root of slope, which is consistent with the LES results and differs from a previously proposed linear trend. The derived scalings provide a potential framework for incorporating slope dependence into parameterizations of mixing and melting at the base of ice shelves. |
format |
Article in Journal/Newspaper |
author |
Anselin, J. Holland, P.R. Jenkins, A. Taylor, J.R. |
spellingShingle |
Anselin, J. Holland, P.R. Jenkins, A. Taylor, J.R. Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current |
author_facet |
Anselin, J. Holland, P.R. Jenkins, A. Taylor, J.R. |
author_sort |
Anselin, J. |
title |
Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current |
title_short |
Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current |
title_full |
Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current |
title_fullStr |
Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current |
title_full_unstemmed |
Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current |
title_sort |
ice base slope effects on the turbulent ice shelf–ocean boundary current |
publisher |
American Meteorological Society |
publishDate |
2024 |
url |
http://nora.nerc.ac.uk/id/eprint/536538/ https://nora.nerc.ac.uk/id/eprint/536538/1/phoc-JPO-D-23-0256.1.pdf https://journals.ametsoc.org/view/journals/phoc/54/7/JPO-D-23-0256.1.xml |
genre |
Antarc* Antarctic Ice Shelf Ice Shelves |
genre_facet |
Antarc* Antarctic Ice Shelf Ice Shelves |
op_relation |
https://nora.nerc.ac.uk/id/eprint/536538/1/phoc-JPO-D-23-0256.1.pdf Anselin, J. orcid:0000-0003-4057-3869 Holland, P.R. orcid:0000-0001-8370-289X Jenkins, A.; Taylor, J.R. 2024 Ice Base Slope Effects on the Turbulent Ice Shelf–Ocean Boundary Current. Journal of Physical Oceanography, 54 (7). 1545-1562. https://doi.org/10.1175/JPO-D-23-0256.1 <https://doi.org/10.1175/JPO-D-23-0256.1> |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.1175/JPO-D-23-0256.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
54 |
container_issue |
7 |
container_start_page |
1545 |
op_container_end_page |
1562 |
_version_ |
1810490327065165824 |