Assessment of sub-shelf melting parameterisations using the ocean–ice-sheet coupled model NEMO(v3.6)–Elmer/Ice(v8.3)
Oceanic melting beneath ice shelves is the main driver of the current mass loss of the Antarctic ice sheet and is mostly parameterised in stand-alone ice-sheet modelling. Parameterisations are crude representations of reality, and their response to ocean warming has not been compared to 3-D ocean–ic...
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ftcopernicus:oai:publications.copernicus.org:gmd74326 2023-05-15T13:55:28+02:00 Assessment of sub-shelf melting parameterisations using the ocean–ice-sheet coupled model NEMO(v3.6)–Elmer/Ice(v8.3) Favier, Lionel Jourdain, Nicolas C. Jenkins, Adrian Merino, Nacho Durand, Gaël Gagliardini, Olivier Gillet-Chaulet, Fabien Mathiot, Pierre 2019-06-12 application/pdf https://doi.org/10.5194/gmd-12-2255-2019 https://gmd.copernicus.org/articles/12/2255/2019/ eng eng doi:10.5194/gmd-12-2255-2019 https://gmd.copernicus.org/articles/12/2255/2019/ eISSN: 1991-9603 Text 2019 ftcopernicus https://doi.org/10.5194/gmd-12-2255-2019 2020-07-20T16:22:48Z Oceanic melting beneath ice shelves is the main driver of the current mass loss of the Antarctic ice sheet and is mostly parameterised in stand-alone ice-sheet modelling. Parameterisations are crude representations of reality, and their response to ocean warming has not been compared to 3-D ocean–ice-sheet coupled models. Here, we assess various melting parameterisations ranging from simple scalings with far-field thermal driving to emulators of box and plume models, using a new coupling framework combining the ocean model NEMO and the ice-sheet model Elmer/Ice. We define six idealised one-century scenarios for the far-field ocean ranging from cold to warm, and representative of potential futures for typical Antarctic ice shelves. The scenarios are used to constrain an idealised geometry of the Pine Island glacier representative of a relatively small cavity. Melt rates and sea-level contributions obtained with the parameterised stand-alone ice-sheet model are compared to the coupled model results. The plume parameterisations give good results for cold scenarios but fail and underestimate sea level contribution by tens of percent for warm(ing) scenarios, which may be improved by adapting its empirical scaling. The box parameterisation with five boxes compares fairly well to the coupled results for almost all scenarios, but further work is needed to grasp the correct number of boxes. For simple scalings, the comparison to the coupled framework shows that a quadratic as opposed to linear dependency on thermal forcing is required. In addition, the quadratic dependency is improved when melting depends on both local and non-local, i.e. averaged over the ice shelf, thermal forcing. The results of both the box and the two quadratic parameterisations fall within or close to the coupled model uncertainty. All parameterisations overestimate melting for thin ice shelves while underestimating melting in deep water near the grounding line. Further work is therefore needed to assess the validity of these melting parameteriations in more realistic set-ups. Text Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Pine Island Glacier Copernicus Publications: E-Journals Antarctic Pine Island Glacier ENVELOPE(-101.000,-101.000,-75.000,-75.000) The Antarctic Geoscientific Model Development 12 6 2255 2283 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Oceanic melting beneath ice shelves is the main driver of the current mass loss of the Antarctic ice sheet and is mostly parameterised in stand-alone ice-sheet modelling. Parameterisations are crude representations of reality, and their response to ocean warming has not been compared to 3-D ocean–ice-sheet coupled models. Here, we assess various melting parameterisations ranging from simple scalings with far-field thermal driving to emulators of box and plume models, using a new coupling framework combining the ocean model NEMO and the ice-sheet model Elmer/Ice. We define six idealised one-century scenarios for the far-field ocean ranging from cold to warm, and representative of potential futures for typical Antarctic ice shelves. The scenarios are used to constrain an idealised geometry of the Pine Island glacier representative of a relatively small cavity. Melt rates and sea-level contributions obtained with the parameterised stand-alone ice-sheet model are compared to the coupled model results. The plume parameterisations give good results for cold scenarios but fail and underestimate sea level contribution by tens of percent for warm(ing) scenarios, which may be improved by adapting its empirical scaling. The box parameterisation with five boxes compares fairly well to the coupled results for almost all scenarios, but further work is needed to grasp the correct number of boxes. For simple scalings, the comparison to the coupled framework shows that a quadratic as opposed to linear dependency on thermal forcing is required. In addition, the quadratic dependency is improved when melting depends on both local and non-local, i.e. averaged over the ice shelf, thermal forcing. The results of both the box and the two quadratic parameterisations fall within or close to the coupled model uncertainty. All parameterisations overestimate melting for thin ice shelves while underestimating melting in deep water near the grounding line. Further work is therefore needed to assess the validity of these melting parameteriations in more realistic set-ups. |
format |
Text |
author |
Favier, Lionel Jourdain, Nicolas C. Jenkins, Adrian Merino, Nacho Durand, Gaël Gagliardini, Olivier Gillet-Chaulet, Fabien Mathiot, Pierre |
spellingShingle |
Favier, Lionel Jourdain, Nicolas C. Jenkins, Adrian Merino, Nacho Durand, Gaël Gagliardini, Olivier Gillet-Chaulet, Fabien Mathiot, Pierre Assessment of sub-shelf melting parameterisations using the ocean–ice-sheet coupled model NEMO(v3.6)–Elmer/Ice(v8.3) |
author_facet |
Favier, Lionel Jourdain, Nicolas C. Jenkins, Adrian Merino, Nacho Durand, Gaël Gagliardini, Olivier Gillet-Chaulet, Fabien Mathiot, Pierre |
author_sort |
Favier, Lionel |
title |
Assessment of sub-shelf melting parameterisations using the ocean–ice-sheet coupled model NEMO(v3.6)–Elmer/Ice(v8.3) |
title_short |
Assessment of sub-shelf melting parameterisations using the ocean–ice-sheet coupled model NEMO(v3.6)–Elmer/Ice(v8.3) |
title_full |
Assessment of sub-shelf melting parameterisations using the ocean–ice-sheet coupled model NEMO(v3.6)–Elmer/Ice(v8.3) |
title_fullStr |
Assessment of sub-shelf melting parameterisations using the ocean–ice-sheet coupled model NEMO(v3.6)–Elmer/Ice(v8.3) |
title_full_unstemmed |
Assessment of sub-shelf melting parameterisations using the ocean–ice-sheet coupled model NEMO(v3.6)–Elmer/Ice(v8.3) |
title_sort |
assessment of sub-shelf melting parameterisations using the ocean–ice-sheet coupled model nemo(v3.6)–elmer/ice(v8.3) |
publishDate |
2019 |
url |
https://doi.org/10.5194/gmd-12-2255-2019 https://gmd.copernicus.org/articles/12/2255/2019/ |
long_lat |
ENVELOPE(-101.000,-101.000,-75.000,-75.000) |
geographic |
Antarctic Pine Island Glacier The Antarctic |
geographic_facet |
Antarctic Pine Island Glacier The Antarctic |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Pine Island Glacier |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves Pine Island Glacier |
op_source |
eISSN: 1991-9603 |
op_relation |
doi:10.5194/gmd-12-2255-2019 https://gmd.copernicus.org/articles/12/2255/2019/ |
op_doi |
https://doi.org/10.5194/gmd-12-2255-2019 |
container_title |
Geoscientific Model Development |
container_volume |
12 |
container_issue |
6 |
container_start_page |
2255 |
op_container_end_page |
2283 |
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1766262113108492288 |