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 observed since 1979. In order to gain insight of the processes responsible for this variability, we have analysed in a control simulat...
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2014
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00020399 2023-05-15T13:41:02+02:00 Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback Goosse, H. Zunz, V. 2014-03 electronic https://doi.org/10.5194/tc-8-453-2014 https://noa.gwlb.de/receive/cop_mods_00020399 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020354/tc-8-453-2014.pdf https://tc.copernicus.org/articles/8/453/2014/tc-8-453-2014.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-8-453-2014 https://noa.gwlb.de/receive/cop_mods_00020399 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020354/tc-8-453-2014.pdf https://tc.copernicus.org/articles/8/453/2014/tc-8-453-2014.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2014 ftnonlinearchiv https://doi.org/10.5194/tc-8-453-2014 2022-02-08T22:52:09Z 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 observed since 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 largely imposed 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 influence as 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 Niedersächsisches Online-Archiv NOA Antarctic The Antarctic The Cryosphere 8 2 453 470 |
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English |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Goosse, H. Zunz, V. Decadal trends in the Antarctic sea ice extent ultimately controlled by ice–ocean feedback |
topic_facet |
article Verlagsveröffentlichung |
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 observed since 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 largely imposed 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 influence as the chance to have a large increase in ice extent is higher if starting from a state characterized by a low value. |
format |
Article in Journal/Newspaper |
author |
Goosse, H. Zunz, V. |
author_facet |
Goosse, H. Zunz, V. |
author_sort |
Goosse, H. |
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 Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/tc-8-453-2014 https://noa.gwlb.de/receive/cop_mods_00020399 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020354/tc-8-453-2014.pdf https://tc.copernicus.org/articles/8/453/2014/tc-8-453-2014.pdf |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Sea ice The Cryosphere |
genre_facet |
Antarc* Antarctic Sea ice The Cryosphere |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-8-453-2014 https://noa.gwlb.de/receive/cop_mods_00020399 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020354/tc-8-453-2014.pdf https://tc.copernicus.org/articles/8/453/2014/tc-8-453-2014.pdf |
op_rights |
uneingeschränkt 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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1766144803432562688 |