Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions
Since 1979 when continuous satellite observations began, Southern Ocean sea ice cover has increased, whilst global coupled climate models simulate a decrease over the same period. It is uncertain whether the observed trends are anthropogenically forced or due to internal variability, or whether the...
Published in: | Journal of Geophysical Research: Oceans |
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ftnerc:oai:nora.nerc.ac.uk:514812 2023-05-15T13:49:33+02:00 Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions Hobbs, Will Curran, Mark Abram, Nerilie Thomas, Elizabeth R. 2016-10 text http://nora.nerc.ac.uk/id/eprint/514812/ https://nora.nerc.ac.uk/id/eprint/514812/1/Hobbs_et_al-2016-Journal_of_Geophysical_Research__Oceans.pdf https://doi.org/10.1002/2016JC012111 en eng Wiley https://nora.nerc.ac.uk/id/eprint/514812/1/Hobbs_et_al-2016-Journal_of_Geophysical_Research__Oceans.pdf Hobbs, Will; Curran, Mark; Abram, Nerilie; Thomas, Elizabeth R. orcid:0000-0002-3010-6493 . 2016 Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions. Journal of Geophysical Research: Oceans, 121 (10). 7804-7818. https://doi.org/10.1002/2016JC012111 <https://doi.org/10.1002/2016JC012111> Publication - Article PeerReviewed 2016 ftnerc https://doi.org/10.1002/2016JC012111 2023-02-04T19:43:44Z Since 1979 when continuous satellite observations began, Southern Ocean sea ice cover has increased, whilst global coupled climate models simulate a decrease over the same period. It is uncertain whether the observed trends are anthropogenically forced or due to internal variability, or whether the apparent discrepancy between models and observations can be explained by internal variability. The shortness of the satellite record is one source of this uncertainty, and a possible solution is to use proxy reconstructions, which extend the analysis period but at the expense of higher observational uncertainty. In this work, we evaluate the utility for change detection of 20th century Southern Ocean sea ice proxies. We find that there are reliable proxies for the East Antarctic, Amundsen, Bellingshausen and Weddell sectors in late winter, and for the Weddell Sea in late autumn. Models and reconstructions agree that sea ice extent in the East Antarctic, Amundsen and Bellingshausen Seas has decreased since the early 1970s, consistent with an anthropogenic response. However, the decrease is small compared to internal variability, and the change is not robustly detectable. We also find that optimal fingerprinting filters out much of the uncertainty in proxy reconstructions. The Ross Sea is a confounding factor, with a significant increase in sea ice since 1979 that is not captured by climate models; however, existing proxy reconstructions of this region are not yet sufficiently reliable for formal change detection. Article in Journal/Newspaper Antarc* Antarctic Ross Sea Sea ice Southern Ocean Weddell Sea Natural Environment Research Council: NERC Open Research Archive Antarctic Southern Ocean Weddell Sea Ross Sea Weddell Journal of Geophysical Research: Oceans 121 10 7804 7818 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Since 1979 when continuous satellite observations began, Southern Ocean sea ice cover has increased, whilst global coupled climate models simulate a decrease over the same period. It is uncertain whether the observed trends are anthropogenically forced or due to internal variability, or whether the apparent discrepancy between models and observations can be explained by internal variability. The shortness of the satellite record is one source of this uncertainty, and a possible solution is to use proxy reconstructions, which extend the analysis period but at the expense of higher observational uncertainty. In this work, we evaluate the utility for change detection of 20th century Southern Ocean sea ice proxies. We find that there are reliable proxies for the East Antarctic, Amundsen, Bellingshausen and Weddell sectors in late winter, and for the Weddell Sea in late autumn. Models and reconstructions agree that sea ice extent in the East Antarctic, Amundsen and Bellingshausen Seas has decreased since the early 1970s, consistent with an anthropogenic response. However, the decrease is small compared to internal variability, and the change is not robustly detectable. We also find that optimal fingerprinting filters out much of the uncertainty in proxy reconstructions. The Ross Sea is a confounding factor, with a significant increase in sea ice since 1979 that is not captured by climate models; however, existing proxy reconstructions of this region are not yet sufficiently reliable for formal change detection. |
format |
Article in Journal/Newspaper |
author |
Hobbs, Will Curran, Mark Abram, Nerilie Thomas, Elizabeth R. |
spellingShingle |
Hobbs, Will Curran, Mark Abram, Nerilie Thomas, Elizabeth R. Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions |
author_facet |
Hobbs, Will Curran, Mark Abram, Nerilie Thomas, Elizabeth R. |
author_sort |
Hobbs, Will |
title |
Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions |
title_short |
Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions |
title_full |
Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions |
title_fullStr |
Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions |
title_full_unstemmed |
Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions |
title_sort |
century-scale perspectives on observed and simulated southern ocean sea ice trends from proxy reconstructions |
publisher |
Wiley |
publishDate |
2016 |
url |
http://nora.nerc.ac.uk/id/eprint/514812/ https://nora.nerc.ac.uk/id/eprint/514812/1/Hobbs_et_al-2016-Journal_of_Geophysical_Research__Oceans.pdf https://doi.org/10.1002/2016JC012111 |
geographic |
Antarctic Southern Ocean Weddell Sea Ross Sea Weddell |
geographic_facet |
Antarctic Southern Ocean Weddell Sea Ross Sea Weddell |
genre |
Antarc* Antarctic Ross Sea Sea ice Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic Ross Sea Sea ice Southern Ocean Weddell Sea |
op_relation |
https://nora.nerc.ac.uk/id/eprint/514812/1/Hobbs_et_al-2016-Journal_of_Geophysical_Research__Oceans.pdf Hobbs, Will; Curran, Mark; Abram, Nerilie; Thomas, Elizabeth R. orcid:0000-0002-3010-6493 . 2016 Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions. Journal of Geophysical Research: Oceans, 121 (10). 7804-7818. https://doi.org/10.1002/2016JC012111 <https://doi.org/10.1002/2016JC012111> |
op_doi |
https://doi.org/10.1002/2016JC012111 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
121 |
container_issue |
10 |
container_start_page |
7804 |
op_container_end_page |
7818 |
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1766251571352436736 |