Improving Antarctic Bottom Water precursors in NEMO for climate applications
The world's largest ice shelves are found in the Antarctic Weddell Sea and Ross Sea where complex interactions between the atmosphere, sea ice, ice shelves and ocean transform shelf waters into High Salinity Shelf Water (HSSW) and Ice Shelf Water (ISW), the parent waters of Antarctic Bottom Wat...
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Copernicus Publications
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Online Access: | https://doi.org/10.5194/gmd-16-3629-2023 https://doaj.org/article/723d390541684a958e6513d895e1382b |
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ftdoajarticles:oai:doaj.org/article:723d390541684a958e6513d895e1382b 2023-07-23T04:14:15+02:00 Improving Antarctic Bottom Water precursors in NEMO for climate applications K. Hutchinson J. Deshayes C. Éthé C. Rousset C. de Lavergne M. Vancoppenolle N. C. Jourdain P. Mathiot 2023-06-01T00:00:00Z https://doi.org/10.5194/gmd-16-3629-2023 https://doaj.org/article/723d390541684a958e6513d895e1382b EN eng Copernicus Publications https://gmd.copernicus.org/articles/16/3629/2023/gmd-16-3629-2023.pdf https://doaj.org/toc/1991-959X https://doaj.org/toc/1991-9603 doi:10.5194/gmd-16-3629-2023 1991-959X 1991-9603 https://doaj.org/article/723d390541684a958e6513d895e1382b Geoscientific Model Development, Vol 16, Pp 3629-3650 (2023) Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.5194/gmd-16-3629-2023 2023-07-02T00:34:35Z The world's largest ice shelves are found in the Antarctic Weddell Sea and Ross Sea where complex interactions between the atmosphere, sea ice, ice shelves and ocean transform shelf waters into High Salinity Shelf Water (HSSW) and Ice Shelf Water (ISW), the parent waters of Antarctic Bottom Water (AABW). This process feeds the lower limb of the global overturning circulation as AABW, the world's densest and deepest water mass, spreads outwards from Antarctica. None of the coupled climate models contributing to CMIP6 directly simulated ocean–ice shelf interactions, thereby omitting a potentially critical piece of the climate puzzle. As a first step towards better representing these processes in a global ocean model, we run a 1 ∘ resolution Nucleus for European Modelling of the Ocean (NEMO; eORCA1) forced configuration to explicitly simulate circulation beneath the Filchner-Ronne Ice Shelf (FRIS), Larsen C Ice Shelf (LCIS) and Ross Ice Shelf (RIS). These locations are thought to supply the majority of the source waters for AABW, and so melt in all other cavities is provisionally prescribed. Results show that the grid resolution of 1 ∘ is sufficient to produce melt rate patterns and total melt fluxes of FRIS (117 ± 21 Gt yr −1 ), LCIS (36 ± 7 Gt yr −1 ) and RIS (112 ± 22 Gt yr −1 ) that agree well with both high-resolution models and satellite measurements. Most notably, allowing sub-ice shelf circulation reduces salinity biases (0.1 psu), produces the previously unresolved water mass ISW and re-organizes the shelf circulation to bring the regional model hydrography closer to observations. A change in AABW within the Weddell Sea and the Ross Sea towards colder, fresher values is identified, but the magnitude is limited by the absence of a realistic overflow. This study presents a NEMO configuration that can be used for climate applications with improved realism of the Antarctic continental shelf circulation and a better representation of the precursors of AABW. Article in Journal/Newspaper Antarc* Antarctic Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Shelf Ice Shelves Ronne Ice Shelf Ross Ice Shelf Ross Sea Sea ice Weddell Sea Directory of Open Access Journals: DOAJ Articles Antarctic Ronne Ice Shelf ENVELOPE(-61.000,-61.000,-78.500,-78.500) Ross Ice Shelf Ross Sea The Antarctic Weddell Weddell Sea Geoscientific Model Development 16 12 3629 3650 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Geology QE1-996.5 |
spellingShingle |
Geology QE1-996.5 K. Hutchinson J. Deshayes C. Éthé C. Rousset C. de Lavergne M. Vancoppenolle N. C. Jourdain P. Mathiot Improving Antarctic Bottom Water precursors in NEMO for climate applications |
topic_facet |
Geology QE1-996.5 |
description |
The world's largest ice shelves are found in the Antarctic Weddell Sea and Ross Sea where complex interactions between the atmosphere, sea ice, ice shelves and ocean transform shelf waters into High Salinity Shelf Water (HSSW) and Ice Shelf Water (ISW), the parent waters of Antarctic Bottom Water (AABW). This process feeds the lower limb of the global overturning circulation as AABW, the world's densest and deepest water mass, spreads outwards from Antarctica. None of the coupled climate models contributing to CMIP6 directly simulated ocean–ice shelf interactions, thereby omitting a potentially critical piece of the climate puzzle. As a first step towards better representing these processes in a global ocean model, we run a 1 ∘ resolution Nucleus for European Modelling of the Ocean (NEMO; eORCA1) forced configuration to explicitly simulate circulation beneath the Filchner-Ronne Ice Shelf (FRIS), Larsen C Ice Shelf (LCIS) and Ross Ice Shelf (RIS). These locations are thought to supply the majority of the source waters for AABW, and so melt in all other cavities is provisionally prescribed. Results show that the grid resolution of 1 ∘ is sufficient to produce melt rate patterns and total melt fluxes of FRIS (117 ± 21 Gt yr −1 ), LCIS (36 ± 7 Gt yr −1 ) and RIS (112 ± 22 Gt yr −1 ) that agree well with both high-resolution models and satellite measurements. Most notably, allowing sub-ice shelf circulation reduces salinity biases (0.1 psu), produces the previously unresolved water mass ISW and re-organizes the shelf circulation to bring the regional model hydrography closer to observations. A change in AABW within the Weddell Sea and the Ross Sea towards colder, fresher values is identified, but the magnitude is limited by the absence of a realistic overflow. This study presents a NEMO configuration that can be used for climate applications with improved realism of the Antarctic continental shelf circulation and a better representation of the precursors of AABW. |
format |
Article in Journal/Newspaper |
author |
K. Hutchinson J. Deshayes C. Éthé C. Rousset C. de Lavergne M. Vancoppenolle N. C. Jourdain P. Mathiot |
author_facet |
K. Hutchinson J. Deshayes C. Éthé C. Rousset C. de Lavergne M. Vancoppenolle N. C. Jourdain P. Mathiot |
author_sort |
K. Hutchinson |
title |
Improving Antarctic Bottom Water precursors in NEMO for climate applications |
title_short |
Improving Antarctic Bottom Water precursors in NEMO for climate applications |
title_full |
Improving Antarctic Bottom Water precursors in NEMO for climate applications |
title_fullStr |
Improving Antarctic Bottom Water precursors in NEMO for climate applications |
title_full_unstemmed |
Improving Antarctic Bottom Water precursors in NEMO for climate applications |
title_sort |
improving antarctic bottom water precursors in nemo for climate applications |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/gmd-16-3629-2023 https://doaj.org/article/723d390541684a958e6513d895e1382b |
long_lat |
ENVELOPE(-61.000,-61.000,-78.500,-78.500) |
geographic |
Antarctic Ronne Ice Shelf Ross Ice Shelf Ross Sea The Antarctic Weddell Weddell Sea |
geographic_facet |
Antarctic Ronne Ice Shelf Ross Ice Shelf Ross Sea The Antarctic Weddell Weddell Sea |
genre |
Antarc* Antarctic Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Shelf Ice Shelves Ronne Ice Shelf Ross Ice Shelf Ross Sea Sea ice Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Shelf Ice Shelves Ronne Ice Shelf Ross Ice Shelf Ross Sea Sea ice Weddell Sea |
op_source |
Geoscientific Model Development, Vol 16, Pp 3629-3650 (2023) |
op_relation |
https://gmd.copernicus.org/articles/16/3629/2023/gmd-16-3629-2023.pdf https://doaj.org/toc/1991-959X https://doaj.org/toc/1991-9603 doi:10.5194/gmd-16-3629-2023 1991-959X 1991-9603 https://doaj.org/article/723d390541684a958e6513d895e1382b |
op_doi |
https://doi.org/10.5194/gmd-16-3629-2023 |
container_title |
Geoscientific Model Development |
container_volume |
16 |
container_issue |
12 |
container_start_page |
3629 |
op_container_end_page |
3650 |
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1772183691439636480 |