Evaluating seasonal sea-ice cover over the Southern Ocean at the Last Glacial Maximum
Southern hemispheric sea-ice impacts ocean circulation and the carbon exchange between the atmosphere and the ocean. Sea-ice is therefore one of the key processes in past and future climate change and variability. As climate models are the only tool available to project future climate change, it is...
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ftdoajarticles:oai:doaj.org/article:73f80e95317e4cd8b26fc104a14a9471 2023-05-15T18:16:07+02:00 Evaluating seasonal sea-ice cover over the Southern Ocean at the Last Glacial Maximum R. A. Green L. Menviel K. J. Meissner X. Crosta D. Chandan G. Lohmann W. R. Peltier X. Shi J. Zhu 2022-04-01T00:00:00Z https://doi.org/10.5194/cp-18-845-2022 https://doaj.org/article/73f80e95317e4cd8b26fc104a14a9471 EN eng Copernicus Publications https://cp.copernicus.org/articles/18/845/2022/cp-18-845-2022.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-18-845-2022 1814-9324 1814-9332 https://doaj.org/article/73f80e95317e4cd8b26fc104a14a9471 Climate of the Past, Vol 18, Pp 845-862 (2022) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2022 ftdoajarticles https://doi.org/10.5194/cp-18-845-2022 2022-12-31T00:08:49Z Southern hemispheric sea-ice impacts ocean circulation and the carbon exchange between the atmosphere and the ocean. Sea-ice is therefore one of the key processes in past and future climate change and variability. As climate models are the only tool available to project future climate change, it is important to assess their performance against observations for a range of different climate states. The Last Glacial Maximum (LGM, ∼21 000 years ago) represents an interesting target as it is a relatively well-documented period with climatic conditions very different from preindustrial conditions. Here, we analyze the LGM seasonal Southern Ocean sea-ice cover as simulated in numerical simulations as part of the Paleoclimate Modelling Intercomparison Project (PMIP) phases 3 and 4. We compare the model outputs to a recently updated compilation of LGM seasonal Southern Ocean sea-ice cover and summer sea surface temperature (SST) to assess the most likely LGM Southern Ocean state. Simulations and paleo-proxy records suggest a fairly well-constrained glacial winter sea-ice edge between 50.5 and 51 ∘ S. However, the spread in simulated glacial summer sea-ice is wide, ranging from almost ice-free conditions to a sea-ice edge reaching 53 ∘ S. Combining model outputs and proxy data, we estimate a likely LGM summer sea-ice edge between 61 and 62 ∘ S and a mean summer sea-ice extent of 14– 15×10 6 km 2 , which is ∼20 %–30 % larger than previous estimates. These estimates point to a higher seasonality of southern hemispheric sea-ice during the LGM than today. We also analyze the main processes defining the summer sea-ice edge within each of the models. We find that summer sea-ice cover is mainly defined by thermodynamic effects in some models, while the sea-ice edge is defined by the position of Southern Ocean upwelling in others. For models included in both PMIP3 and PMIP4, this thermodynamic or dynamic control on sea-ice is consistent across both experiments. Finally, we find that the impact of changes in large-scale ocean ... Article in Journal/Newspaper Sea ice Southern Ocean Directory of Open Access Journals: DOAJ Articles Southern Ocean Climate of the Past 18 4 845 862 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 R. A. Green L. Menviel K. J. Meissner X. Crosta D. Chandan G. Lohmann W. R. Peltier X. Shi J. Zhu Evaluating seasonal sea-ice cover over the Southern Ocean at the Last Glacial Maximum |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
Southern hemispheric sea-ice impacts ocean circulation and the carbon exchange between the atmosphere and the ocean. Sea-ice is therefore one of the key processes in past and future climate change and variability. As climate models are the only tool available to project future climate change, it is important to assess their performance against observations for a range of different climate states. The Last Glacial Maximum (LGM, ∼21 000 years ago) represents an interesting target as it is a relatively well-documented period with climatic conditions very different from preindustrial conditions. Here, we analyze the LGM seasonal Southern Ocean sea-ice cover as simulated in numerical simulations as part of the Paleoclimate Modelling Intercomparison Project (PMIP) phases 3 and 4. We compare the model outputs to a recently updated compilation of LGM seasonal Southern Ocean sea-ice cover and summer sea surface temperature (SST) to assess the most likely LGM Southern Ocean state. Simulations and paleo-proxy records suggest a fairly well-constrained glacial winter sea-ice edge between 50.5 and 51 ∘ S. However, the spread in simulated glacial summer sea-ice is wide, ranging from almost ice-free conditions to a sea-ice edge reaching 53 ∘ S. Combining model outputs and proxy data, we estimate a likely LGM summer sea-ice edge between 61 and 62 ∘ S and a mean summer sea-ice extent of 14– 15×10 6 km 2 , which is ∼20 %–30 % larger than previous estimates. These estimates point to a higher seasonality of southern hemispheric sea-ice during the LGM than today. We also analyze the main processes defining the summer sea-ice edge within each of the models. We find that summer sea-ice cover is mainly defined by thermodynamic effects in some models, while the sea-ice edge is defined by the position of Southern Ocean upwelling in others. For models included in both PMIP3 and PMIP4, this thermodynamic or dynamic control on sea-ice is consistent across both experiments. Finally, we find that the impact of changes in large-scale ocean ... |
format |
Article in Journal/Newspaper |
author |
R. A. Green L. Menviel K. J. Meissner X. Crosta D. Chandan G. Lohmann W. R. Peltier X. Shi J. Zhu |
author_facet |
R. A. Green L. Menviel K. J. Meissner X. Crosta D. Chandan G. Lohmann W. R. Peltier X. Shi J. Zhu |
author_sort |
R. A. Green |
title |
Evaluating seasonal sea-ice cover over the Southern Ocean at the Last Glacial Maximum |
title_short |
Evaluating seasonal sea-ice cover over the Southern Ocean at the Last Glacial Maximum |
title_full |
Evaluating seasonal sea-ice cover over the Southern Ocean at the Last Glacial Maximum |
title_fullStr |
Evaluating seasonal sea-ice cover over the Southern Ocean at the Last Glacial Maximum |
title_full_unstemmed |
Evaluating seasonal sea-ice cover over the Southern Ocean at the Last Glacial Maximum |
title_sort |
evaluating seasonal sea-ice cover over the southern ocean at the last glacial maximum |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/cp-18-845-2022 https://doaj.org/article/73f80e95317e4cd8b26fc104a14a9471 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Sea ice Southern Ocean |
genre_facet |
Sea ice Southern Ocean |
op_source |
Climate of the Past, Vol 18, Pp 845-862 (2022) |
op_relation |
https://cp.copernicus.org/articles/18/845/2022/cp-18-845-2022.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-18-845-2022 1814-9324 1814-9332 https://doaj.org/article/73f80e95317e4cd8b26fc104a14a9471 |
op_doi |
https://doi.org/10.5194/cp-18-845-2022 |
container_title |
Climate of the Past |
container_volume |
18 |
container_issue |
4 |
container_start_page |
845 |
op_container_end_page |
862 |
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1766189559100473344 |