Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales
We investigate the individual and joint decadal variability of Southern Ocean state quantities, such as the strength of the Ross and Weddell Gyres, Drake Passage transport, and sea ice area, using the National Institute of Water and Atmospheric Research UK Chemistry and Aerosols (NIWA-UKCA) model an...
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ftuniveastangl:oai:ueaeprints.uea.ac.uk:58737 2023-05-15T13:45:56+02:00 Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales Behrens, Erik Rickard, Graham Morgenstern, Olaf Martin, Torge Osprey, Annette Joshi, Manoj 2016-06 application/pdf https://ueaeprints.uea.ac.uk/id/eprint/58737/ https://ueaeprints.uea.ac.uk/id/eprint/58737/11/Behrens_et_al_2016_Journal_of_Geophysical_Research_Oceans.pdf https://doi.org/10.1002/2015JC011286 en eng https://ueaeprints.uea.ac.uk/id/eprint/58737/11/Behrens_et_al_2016_Journal_of_Geophysical_Research_Oceans.pdf Behrens, Erik, Rickard, Graham, Morgenstern, Olaf, Martin, Torge, Osprey, Annette and Joshi, Manoj (2016) Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales. Journal of Geophysical Research C: Oceans, 121 (6). pp. 3905-3925. doi:10.1002/2015JC011286 Article PeerReviewed 2016 ftuniveastangl https://doi.org/10.1002/2015JC011286 2023-01-30T21:43:44Z We investigate the individual and joint decadal variability of Southern Ocean state quantities, such as the strength of the Ross and Weddell Gyres, Drake Passage transport, and sea ice area, using the National Institute of Water and Atmospheric Research UK Chemistry and Aerosols (NIWA-UKCA) model and CMIP5 models. Variability in these quantities is stimulated by strong deep reaching convective events in the Southern Ocean, which produce an Antarctic Bottom Water-like water mass and affect the large-scale meridional density structure in the Southern Ocean. An increase in the (near) surface stratification, due to freshwater forcing, can be a precondition for subsequent strong convection activity. The combination of enhanced-gyre driven sea ice and freshwater export, as well as ongoing subsurface heat accumulation, lead to a time lag between changes in oceanic freshwater and heat content. This causes an ongoing weakening of the stratification until sudden strong mixing events emerge and the heat is released to the atmosphere. We find that strong convection reduces sea ice cover, weakens the subpolar gyres, increases the meridional density gradient and subsequently results in a positive Drake Passage transport anomaly. Results of available CMIP5 models confirm that variability in sea ice, Drake Passage transport, and the Weddell Gyre strength is enhanced if models show strong open ocean convective events. Consistent relationships between convection, sea ice, Drake Passage transport, and Ross Gyre strength variability are evident in most models, whether or not they host open ocean convection. Article in Journal/Newspaper Antarc* Antarctic Drake Passage Sea ice Southern Ocean University of East Anglia: UEA Digital Repository Antarctic Drake Passage Southern Ocean Weddell Journal of Geophysical Research: Oceans 121 6 3905 3925 |
institution |
Open Polar |
collection |
University of East Anglia: UEA Digital Repository |
op_collection_id |
ftuniveastangl |
language |
English |
description |
We investigate the individual and joint decadal variability of Southern Ocean state quantities, such as the strength of the Ross and Weddell Gyres, Drake Passage transport, and sea ice area, using the National Institute of Water and Atmospheric Research UK Chemistry and Aerosols (NIWA-UKCA) model and CMIP5 models. Variability in these quantities is stimulated by strong deep reaching convective events in the Southern Ocean, which produce an Antarctic Bottom Water-like water mass and affect the large-scale meridional density structure in the Southern Ocean. An increase in the (near) surface stratification, due to freshwater forcing, can be a precondition for subsequent strong convection activity. The combination of enhanced-gyre driven sea ice and freshwater export, as well as ongoing subsurface heat accumulation, lead to a time lag between changes in oceanic freshwater and heat content. This causes an ongoing weakening of the stratification until sudden strong mixing events emerge and the heat is released to the atmosphere. We find that strong convection reduces sea ice cover, weakens the subpolar gyres, increases the meridional density gradient and subsequently results in a positive Drake Passage transport anomaly. Results of available CMIP5 models confirm that variability in sea ice, Drake Passage transport, and the Weddell Gyre strength is enhanced if models show strong open ocean convective events. Consistent relationships between convection, sea ice, Drake Passage transport, and Ross Gyre strength variability are evident in most models, whether or not they host open ocean convection. |
format |
Article in Journal/Newspaper |
author |
Behrens, Erik Rickard, Graham Morgenstern, Olaf Martin, Torge Osprey, Annette Joshi, Manoj |
spellingShingle |
Behrens, Erik Rickard, Graham Morgenstern, Olaf Martin, Torge Osprey, Annette Joshi, Manoj Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales |
author_facet |
Behrens, Erik Rickard, Graham Morgenstern, Olaf Martin, Torge Osprey, Annette Joshi, Manoj |
author_sort |
Behrens, Erik |
title |
Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales |
title_short |
Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales |
title_full |
Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales |
title_fullStr |
Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales |
title_full_unstemmed |
Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales |
title_sort |
southern ocean deep convection in global climate models: a driver for variability of subpolar gyres and drake passage transport on decadal time scales |
publishDate |
2016 |
url |
https://ueaeprints.uea.ac.uk/id/eprint/58737/ https://ueaeprints.uea.ac.uk/id/eprint/58737/11/Behrens_et_al_2016_Journal_of_Geophysical_Research_Oceans.pdf https://doi.org/10.1002/2015JC011286 |
geographic |
Antarctic Drake Passage Southern Ocean Weddell |
geographic_facet |
Antarctic Drake Passage Southern Ocean Weddell |
genre |
Antarc* Antarctic Drake Passage Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Drake Passage Sea ice Southern Ocean |
op_relation |
https://ueaeprints.uea.ac.uk/id/eprint/58737/11/Behrens_et_al_2016_Journal_of_Geophysical_Research_Oceans.pdf Behrens, Erik, Rickard, Graham, Morgenstern, Olaf, Martin, Torge, Osprey, Annette and Joshi, Manoj (2016) Southern Ocean deep convection in global climate models: A driver for variability of subpolar gyres and Drake Passage transport on decadal time scales. Journal of Geophysical Research C: Oceans, 121 (6). pp. 3905-3925. doi:10.1002/2015JC011286 |
op_doi |
https://doi.org/10.1002/2015JC011286 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
121 |
container_issue |
6 |
container_start_page |
3905 |
op_container_end_page |
3925 |
_version_ |
1766232904305737728 |