How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent?
Observations over the last 30 yr have shown that the sea ice extent in the Southern Ocean has slightly increased since 1979. Mechanisms responsible for this positive trend have not been well established yet. In this study we tackle two related issues: is the observed positive trend compatible with t...
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ftcopernicus:oai:publications.copernicus.org:tc16464 2023-05-15T13:54:27+02:00 How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent? Zunz, V. Goosse, H. Massonnet, F. 2018-09-27 application/pdf https://doi.org/10.5194/tc-7-451-2013 https://tc.copernicus.org/articles/7/451/2013/ eng eng doi:10.5194/tc-7-451-2013 https://tc.copernicus.org/articles/7/451/2013/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-7-451-2013 2020-07-20T16:25:32Z Observations over the last 30 yr have shown that the sea ice extent in the Southern Ocean has slightly increased since 1979. Mechanisms responsible for this positive trend have not been well established yet. In this study we tackle two related issues: is the observed positive trend compatible with the internal variability of the system, and do the models agree with what we know about the observed internal variability? For that purpose, we analyse the evolution of sea ice around the Antarctic simulated by 24 different general circulation models involved in the 5th Coupled Model Intercomparison Project (CMIP5), using both historical and hindcast experiments. Our analyses show that CMIP5 models respond to the forcing, including the one induced by stratospheric ozone depletion, by reducing the sea ice cover in the Southern Ocean. Some simulations display an increase in sea ice extent similar to the observed one. According to models, the observed positive trend is compatible with internal variability. However, models strongly overestimate the variance of sea ice extent and the initialization methods currently used in models do not improve systematically the simulated trends in sea ice extent. On the basis of those results, a critical role of the internal variability in the observed increase of sea ice extent in the Southern Ocean could not be ruled out, but current models results appear inadequate to test more precisely this hypothesis. Text Antarc* Antarctic Sea ice Southern Ocean Copernicus Publications: E-Journals Antarctic Southern Ocean The Antarctic The Cryosphere 7 2 451 468 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
Observations over the last 30 yr have shown that the sea ice extent in the Southern Ocean has slightly increased since 1979. Mechanisms responsible for this positive trend have not been well established yet. In this study we tackle two related issues: is the observed positive trend compatible with the internal variability of the system, and do the models agree with what we know about the observed internal variability? For that purpose, we analyse the evolution of sea ice around the Antarctic simulated by 24 different general circulation models involved in the 5th Coupled Model Intercomparison Project (CMIP5), using both historical and hindcast experiments. Our analyses show that CMIP5 models respond to the forcing, including the one induced by stratospheric ozone depletion, by reducing the sea ice cover in the Southern Ocean. Some simulations display an increase in sea ice extent similar to the observed one. According to models, the observed positive trend is compatible with internal variability. However, models strongly overestimate the variance of sea ice extent and the initialization methods currently used in models do not improve systematically the simulated trends in sea ice extent. On the basis of those results, a critical role of the internal variability in the observed increase of sea ice extent in the Southern Ocean could not be ruled out, but current models results appear inadequate to test more precisely this hypothesis. |
format |
Text |
author |
Zunz, V. Goosse, H. Massonnet, F. |
spellingShingle |
Zunz, V. Goosse, H. Massonnet, F. How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent? |
author_facet |
Zunz, V. Goosse, H. Massonnet, F. |
author_sort |
Zunz, V. |
title |
How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent? |
title_short |
How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent? |
title_full |
How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent? |
title_fullStr |
How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent? |
title_full_unstemmed |
How does internal variability influence the ability of CMIP5 models to reproduce the recent trend in Southern Ocean sea ice extent? |
title_sort |
how does internal variability influence the ability of cmip5 models to reproduce the recent trend in southern ocean sea ice extent? |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-7-451-2013 https://tc.copernicus.org/articles/7/451/2013/ |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Sea ice Southern Ocean |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-7-451-2013 https://tc.copernicus.org/articles/7/451/2013/ |
op_doi |
https://doi.org/10.5194/tc-7-451-2013 |
container_title |
The Cryosphere |
container_volume |
7 |
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2 |
container_start_page |
451 |
op_container_end_page |
468 |
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1766260381080092672 |