Improving Antarctic Bottom Water precursors in NEMO for climate applications
<p>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 B...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-06-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/16/3629/2023/gmd-16-3629-2023.pdf |
| _version_ | 1797791661026181120 |
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| 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 |
| collection | DOAJ |
| description | <p>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<span class="inline-formula"><sup>∘</sup></span> 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<span class="inline-formula"><sup>∘</sup></span> is sufficient to produce melt rate patterns and total melt
fluxes of FRIS (117 <span class="inline-formula">±</span> 21 Gt yr<span class="inline-formula"><sup>−1</sup></span>), LCIS (36 <span class="inline-formula">±</span> 7 Gt yr<span class="inline-formula"><sup>−1</sup></span>) and RIS
(112 <span class="inline-formula">±</span> 22 Gt yr<span class="inline-formula"><sup>−1</sup></span>) 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.</p> |
| first_indexed | 2024-03-13T02:22:01Z |
| format | Article |
| id | doaj.art-723d390541684a958e6513d895e1382b |
| institution | Directory Open Access Journal |
| issn | 1991-959X 1991-9603 |
| language | English |
| last_indexed | 2024-03-13T02:22:01Z |
| publishDate | 2023-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Geoscientific Model Development |
| spelling | doaj.art-723d390541684a958e6513d895e1382b2023-06-30T08:34:46ZengCopernicus PublicationsGeoscientific Model Development1991-959X1991-96032023-06-01163629365010.5194/gmd-16-3629-2023Improving Antarctic Bottom Water precursors in NEMO for climate applicationsK. Hutchinson0J. Deshayes1C. Éthé2C. Rousset3C. de Lavergne4M. Vancoppenolle5N. C. Jourdain6P. Mathiot7LOCEAN Laboratory, Sorbonne Université CNRS-IRD-MNHN, Paris, FranceLOCEAN Laboratory, Sorbonne Université CNRS-IRD-MNHN, Paris, FranceLOCEAN Laboratory, Sorbonne Université CNRS-IRD-MNHN, Paris, FranceLOCEAN Laboratory, Sorbonne Université CNRS-IRD-MNHN, Paris, FranceLOCEAN Laboratory, Sorbonne Université CNRS-IRD-MNHN, Paris, FranceLOCEAN Laboratory, Sorbonne Université CNRS-IRD-MNHN, Paris, FranceUniversity Grenoble Alpes/CNRS/IRD/G-INP, IGE, Grenoble, FranceUniversity Grenoble Alpes/CNRS/IRD/G-INP, IGE, Grenoble, France<p>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<span class="inline-formula"><sup>∘</sup></span> 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<span class="inline-formula"><sup>∘</sup></span> is sufficient to produce melt rate patterns and total melt fluxes of FRIS (117 <span class="inline-formula">±</span> 21 Gt yr<span class="inline-formula"><sup>−1</sup></span>), LCIS (36 <span class="inline-formula">±</span> 7 Gt yr<span class="inline-formula"><sup>−1</sup></span>) and RIS (112 <span class="inline-formula">±</span> 22 Gt yr<span class="inline-formula"><sup>−1</sup></span>) 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.</p>https://gmd.copernicus.org/articles/16/3629/2023/gmd-16-3629-2023.pdf |
| spellingShingle | 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 Geoscientific Model Development |
| title | 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_short | Improving Antarctic Bottom Water precursors in NEMO for climate applications |
| title_sort | improving antarctic bottom water precursors in nemo for climate applications |
| url | https://gmd.copernicus.org/articles/16/3629/2023/gmd-16-3629-2023.pdf |
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