Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback
The large natural variability of the Antarctic sea ice is a key characteristic of the system that might be responsible for the small positive trend in sea ice extent observedsince 1979. In order to gain insight of the processes responsible for this variability, we have analysed in a control simulati...
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ftunivlouvain:oai:dial.uclouvain.be:boreal:141734 2024-05-19T07:32:23+00:00 Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback Goosse, Hugues Zunz, Violette UCL - SST/ELI/ELIC - Earth & Climate 2014 http://hdl.handle.net/2078.1/141734 https://doi.org/10.5194/tc-8-453-2014 eng eng Copernicus GmbH boreal:141734 http://hdl.handle.net/2078.1/141734 doi:10.5194/tc-8-453-2014 urn:ISSN:1994-0416 urn:EISSN:1994-0424 info:eu-repo/semantics/openAccess The Cryosphere, Vol. 8, no.2, p. 453-470 (2014) CISM:CECI 1443 info:eu-repo/semantics/article 2014 ftunivlouvain https://doi.org/10.5194/tc-8-453-2014 2024-04-24T01:35:37Z The large natural variability of the Antarctic sea ice is a key characteristic of the system that might be responsible for the small positive trend in sea ice extent observedsince 1979. In order to gain insight of the processes responsible for this variability, we have analysed in a control simulation performed with a coupled climate model a positive ice–ocean feedback that amplifies sea ice variations. When sea ice concentration increases in a region, in particular close to the ice edge, the mixed layer depth tends to decrease. This can be caused by a net inflow of ice, and thus of freshwater, that stabilizes the water column. A second stabilizing mechanism at interannual timescales is associated with the downward salt transport due to the seasonal cycle of ice formation: brine is released in winter and mixed over a deep layer while the freshwater flux caused by ice melting is included in a shallow layer, resulting in a net vertical transport of salt. Because of this stronger stratification due to the presence of sea ice, more heat is stored at depth in the ocean and the vertical oceanic heat flux is reduced, which contributes to maintaining a higher ice extent. This positive feedback is not associated with a particular spatial pattern. Consequently, the spatial distribution of the trend in ice concentration is largelyimposed by the wind changes that can provide the initial perturbation. A positive freshwater flux could alternatively be the initial trigger but the amplitude of the final response of the sea ice extent is finally set up by the amplification related to the ice–ocean feedback. Initial conditions also have an influenceas the chance to have a large increase in ice extent is higher if starting from a state characterized by a low value. Article in Journal/Newspaper Antarc* Antarctic Sea ice The Cryosphere DIAL@UCLouvain (Université catholique de Louvain) The Cryosphere 8 2 453 470 |
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Open Polar |
collection |
DIAL@UCLouvain (Université catholique de Louvain) |
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ftunivlouvain |
language |
English |
topic |
CISM:CECI 1443 |
spellingShingle |
CISM:CECI 1443 Goosse, Hugues Zunz, Violette Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback |
topic_facet |
CISM:CECI 1443 |
description |
The large natural variability of the Antarctic sea ice is a key characteristic of the system that might be responsible for the small positive trend in sea ice extent observedsince 1979. In order to gain insight of the processes responsible for this variability, we have analysed in a control simulation performed with a coupled climate model a positive ice–ocean feedback that amplifies sea ice variations. When sea ice concentration increases in a region, in particular close to the ice edge, the mixed layer depth tends to decrease. This can be caused by a net inflow of ice, and thus of freshwater, that stabilizes the water column. A second stabilizing mechanism at interannual timescales is associated with the downward salt transport due to the seasonal cycle of ice formation: brine is released in winter and mixed over a deep layer while the freshwater flux caused by ice melting is included in a shallow layer, resulting in a net vertical transport of salt. Because of this stronger stratification due to the presence of sea ice, more heat is stored at depth in the ocean and the vertical oceanic heat flux is reduced, which contributes to maintaining a higher ice extent. This positive feedback is not associated with a particular spatial pattern. Consequently, the spatial distribution of the trend in ice concentration is largelyimposed by the wind changes that can provide the initial perturbation. A positive freshwater flux could alternatively be the initial trigger but the amplitude of the final response of the sea ice extent is finally set up by the amplification related to the ice–ocean feedback. Initial conditions also have an influenceas the chance to have a large increase in ice extent is higher if starting from a state characterized by a low value. |
author2 |
UCL - SST/ELI/ELIC - Earth & Climate |
format |
Article in Journal/Newspaper |
author |
Goosse, Hugues Zunz, Violette |
author_facet |
Goosse, Hugues Zunz, Violette |
author_sort |
Goosse, Hugues |
title |
Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback |
title_short |
Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback |
title_full |
Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback |
title_fullStr |
Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback |
title_full_unstemmed |
Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback |
title_sort |
decadal trends in the antarctic sea ice extent ultimately controlled by ice–ocean feedback |
publisher |
Copernicus GmbH |
publishDate |
2014 |
url |
http://hdl.handle.net/2078.1/141734 https://doi.org/10.5194/tc-8-453-2014 |
genre |
Antarc* Antarctic Sea ice The Cryosphere |
genre_facet |
Antarc* Antarctic Sea ice The Cryosphere |
op_source |
The Cryosphere, Vol. 8, no.2, p. 453-470 (2014) |
op_relation |
boreal:141734 http://hdl.handle.net/2078.1/141734 doi:10.5194/tc-8-453-2014 urn:ISSN:1994-0416 urn:EISSN:1994-0424 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/tc-8-453-2014 |
container_title |
The Cryosphere |
container_volume |
8 |
container_issue |
2 |
container_start_page |
453 |
op_container_end_page |
470 |
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1799470421677965312 |