North Atlantic climate responses to perturbations in Antarctic Intermediate Water
Recent observations suggest Antarctic Intermediate Water (AAIW) properties are changing. The impact of such variations is explored using idealised perturbation experiments with a coupled climate model, HadCM3. AAIW properties are altered between 10 and 20°S in the South Atlantic, maintaining constan...
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ftuniveastangl:oai:ueaeprints.uea.ac.uk:19461 2023-06-06T11:46:49+02:00 North Atlantic climate responses to perturbations in Antarctic Intermediate Water Graham, Jennifer A. Stevens, David P. Heywood, Karen J. Wang, Zhaomin 2011 application/pdf https://ueaeprints.uea.ac.uk/id/eprint/19461/ https://ueaeprints.uea.ac.uk/id/eprint/19461/1/DS_54.pdf https://doi.org/10.1007/s00382-010-0981-1 en eng https://ueaeprints.uea.ac.uk/id/eprint/19461/1/DS_54.pdf Graham, Jennifer A., Stevens, David P., Heywood, Karen J. and Wang, Zhaomin (2011) North Atlantic climate responses to perturbations in Antarctic Intermediate Water. Climate Dynamics, 37 (1-2). pp. 297-311. doi:10.1007/s00382-010-0981-1 Article PeerReviewed 2011 ftuniveastangl https://doi.org/10.1007/s00382-010-0981-1 2023-04-13T22:31:21Z Recent observations suggest Antarctic Intermediate Water (AAIW) properties are changing. The impact of such variations is explored using idealised perturbation experiments with a coupled climate model, HadCM3. AAIW properties are altered between 10 and 20°S in the South Atlantic, maintaining constant potential density. The perturbed AAIW remains subsurface in the South Atlantic, but as it moves northwards, it surfaces and interacts with the atmosphere leading to density anomalies due to heat exchanges. For a cooler, fresher AAIW, there is a significant decrease in the mean North Atlantic sea surface temperature (SST), of up to 1°C, during years 51-100. In the North Atlantic Current region there are persistent cold anomalies from 2,000 m depth to the surface, and in the overlying atmosphere. Atmospheric surface pressure increases over the mid-latitude Atlantic, and precipitation decreases over northwest Africa and southwest Europe. Surface heat flux anomalies show that these impacts are caused by changes in the ocean rather than atmospheric forcing. The SST response is associated with significant changes in the Atlantic meridional overturning circulation (MOC). After 50 years there is a decrease in the MOC that persists for the remainder of the simulation, resulting from changes in the column-averaged density difference between 30°S and 60°N. Rather than showing a linear response, a warmer, saltier AAIW also leads to a decreased MOC strength for years 51-100 and resulting cooling in the North Atlantic. The non-linearity can be attributed to opposing density responses as the perturbed water masses interact with the atmosphere. Article in Journal/Newspaper Antarc* Antarctic north atlantic current North Atlantic University of East Anglia: UEA Digital Repository Antarctic Climate Dynamics 37 1-2 297 311 |
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University of East Anglia: UEA Digital Repository |
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ftuniveastangl |
language |
English |
description |
Recent observations suggest Antarctic Intermediate Water (AAIW) properties are changing. The impact of such variations is explored using idealised perturbation experiments with a coupled climate model, HadCM3. AAIW properties are altered between 10 and 20°S in the South Atlantic, maintaining constant potential density. The perturbed AAIW remains subsurface in the South Atlantic, but as it moves northwards, it surfaces and interacts with the atmosphere leading to density anomalies due to heat exchanges. For a cooler, fresher AAIW, there is a significant decrease in the mean North Atlantic sea surface temperature (SST), of up to 1°C, during years 51-100. In the North Atlantic Current region there are persistent cold anomalies from 2,000 m depth to the surface, and in the overlying atmosphere. Atmospheric surface pressure increases over the mid-latitude Atlantic, and precipitation decreases over northwest Africa and southwest Europe. Surface heat flux anomalies show that these impacts are caused by changes in the ocean rather than atmospheric forcing. The SST response is associated with significant changes in the Atlantic meridional overturning circulation (MOC). After 50 years there is a decrease in the MOC that persists for the remainder of the simulation, resulting from changes in the column-averaged density difference between 30°S and 60°N. Rather than showing a linear response, a warmer, saltier AAIW also leads to a decreased MOC strength for years 51-100 and resulting cooling in the North Atlantic. The non-linearity can be attributed to opposing density responses as the perturbed water masses interact with the atmosphere. |
format |
Article in Journal/Newspaper |
author |
Graham, Jennifer A. Stevens, David P. Heywood, Karen J. Wang, Zhaomin |
spellingShingle |
Graham, Jennifer A. Stevens, David P. Heywood, Karen J. Wang, Zhaomin North Atlantic climate responses to perturbations in Antarctic Intermediate Water |
author_facet |
Graham, Jennifer A. Stevens, David P. Heywood, Karen J. Wang, Zhaomin |
author_sort |
Graham, Jennifer A. |
title |
North Atlantic climate responses to perturbations in Antarctic Intermediate Water |
title_short |
North Atlantic climate responses to perturbations in Antarctic Intermediate Water |
title_full |
North Atlantic climate responses to perturbations in Antarctic Intermediate Water |
title_fullStr |
North Atlantic climate responses to perturbations in Antarctic Intermediate Water |
title_full_unstemmed |
North Atlantic climate responses to perturbations in Antarctic Intermediate Water |
title_sort |
north atlantic climate responses to perturbations in antarctic intermediate water |
publishDate |
2011 |
url |
https://ueaeprints.uea.ac.uk/id/eprint/19461/ https://ueaeprints.uea.ac.uk/id/eprint/19461/1/DS_54.pdf https://doi.org/10.1007/s00382-010-0981-1 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic north atlantic current North Atlantic |
genre_facet |
Antarc* Antarctic north atlantic current North Atlantic |
op_relation |
https://ueaeprints.uea.ac.uk/id/eprint/19461/1/DS_54.pdf Graham, Jennifer A., Stevens, David P., Heywood, Karen J. and Wang, Zhaomin (2011) North Atlantic climate responses to perturbations in Antarctic Intermediate Water. Climate Dynamics, 37 (1-2). pp. 297-311. doi:10.1007/s00382-010-0981-1 |
op_doi |
https://doi.org/10.1007/s00382-010-0981-1 |
container_title |
Climate Dynamics |
container_volume |
37 |
container_issue |
1-2 |
container_start_page |
297 |
op_container_end_page |
311 |
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1767952278363308032 |