Memory Effect of the Southern Atlantic Subtropical Dipole

The South Atlantic subtropical dipole is the dominant mode of coupled variability in the South Atlantic, connecting sea level pressure and sea surface temperature. Previous studies have shown its great relevance to the climate conditions over South America and West Africa. We have used several numer...

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التفاصيل البيبلوغرافية
المؤلف الرئيسي: Santis, Wlademir (author)
مؤلفون آخرون: Castellanos, Paola (author), Campos, Edmo (author)
التنسيق: article
منشور في: 2020
الموضوعات:
الوصول للمادة أونلاين:http://hdl.handle.net/11073/19714
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author Santis, Wlademir
author2 Castellanos, Paola
Campos, Edmo
author2_role author
author
author_facet Santis, Wlademir
Castellanos, Paola
Campos, Edmo
author_role author
dc.creator.none.fl_str_mv Santis, Wlademir
Castellanos, Paola
Campos, Edmo
dc.date.none.fl_str_mv 2020-08-10T12:56:31Z
2020-08-10T12:56:31Z
2020-08-04
dc.format.none.fl_str_mv application/pdf
dc.identifier.none.fl_str_mv Santis, W., Castellanos, P., & Campos, E. (2020). Memory effect of the Southern Atlantic subtropical dipole. Journal of Climate, 33(17), 7679– 7696. https://doi.org/10.1175/JCLI-D-19-0745.1
1520-0442
http://hdl.handle.net/11073/19714
10.1175/JCLI-D-19-0745.1
dc.language.none.fl_str_mv en_US
dc.publisher.none.fl_str_mv American Meteorological Society
dc.relation.none.fl_str_mv https://doi.org/10.1175/JCLI-D-19-0745.1
dc.subject.none.fl_str_mv Atmosphere
Ocean
South Atlantic Ocean
Atmosphere-ocean interaction
Entrainment
Mixed layer
dc.title.none.fl_str_mv Memory Effect of the Southern Atlantic Subtropical Dipole
dc.type.none.fl_str_mv Peer-Reviewed
Published version
info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/article
description The South Atlantic subtropical dipole is the dominant mode of coupled variability in the South Atlantic, connecting sea level pressure and sea surface temperature. Previous studies have shown its great relevance to the climate conditions over South America and West Africa. We have used several numerical experiments with the Hybrid Coordinate Ocean Model to investigate the effects that an austral winter-spring dipole asserts on the South Atlantic. We explore the interaction between SST anomalies and the formation of the fossilized mixing region, which preserve temperature anomalies underneath the summer mixed layer, until they feed back to SST after the next autumn. It was found that, through this process, there is a memory effect that restores temperature anomalies from an austral winter–spring dipole back to the austral winter of the following year. The dominant mechanisms are the contribution from entrainment and surface net heat flux (NHF). Entrainment is mostly controlled by vertical temperature gradient anomalies, while surface NHF is controlled by interactions of climatological ocean heat loss and anomalies of mixed layer thickness. Our results suggest that the combined effect of entrainment and surface NHF is different in the southwest and northeast dipole regions, leading to differences in both intensity and timing of SST anomalies. Turbulent and nonlinear processes are most important to reduce entrainment in the southwest dipole region and to increase the memory effect asymmetry.
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identifier_str_mv Santis, W., Castellanos, P., & Campos, E. (2020). Memory effect of the Southern Atlantic subtropical dipole. Journal of Climate, 33(17), 7679– 7696. https://doi.org/10.1175/JCLI-D-19-0745.1
1520-0442
10.1175/JCLI-D-19-0745.1
language_invalid_str_mv en_US
network_acronym_str aus
network_name_str aus
oai_identifier_str oai:repository.aus.edu:11073/19714
publishDate 2020
publisher.none.fl_str_mv American Meteorological Society
repository.mail.fl_str_mv
repository.name.fl_str_mv
repository_id_str
spelling Memory Effect of the Southern Atlantic Subtropical DipoleSantis, WlademirCastellanos, PaolaCampos, EdmoAtmosphereOceanSouth Atlantic OceanAtmosphere-ocean interactionEntrainmentMixed layerThe South Atlantic subtropical dipole is the dominant mode of coupled variability in the South Atlantic, connecting sea level pressure and sea surface temperature. Previous studies have shown its great relevance to the climate conditions over South America and West Africa. We have used several numerical experiments with the Hybrid Coordinate Ocean Model to investigate the effects that an austral winter-spring dipole asserts on the South Atlantic. We explore the interaction between SST anomalies and the formation of the fossilized mixing region, which preserve temperature anomalies underneath the summer mixed layer, until they feed back to SST after the next autumn. It was found that, through this process, there is a memory effect that restores temperature anomalies from an austral winter–spring dipole back to the austral winter of the following year. The dominant mechanisms are the contribution from entrainment and surface net heat flux (NHF). Entrainment is mostly controlled by vertical temperature gradient anomalies, while surface NHF is controlled by interactions of climatological ocean heat loss and anomalies of mixed layer thickness. Our results suggest that the combined effect of entrainment and surface NHF is different in the southwest and northeast dipole regions, leading to differences in both intensity and timing of SST anomalies. Turbulent and nonlinear processes are most important to reduce entrainment in the southwest dipole region and to increase the memory effect asymmetry.São Paulo State Foundation for Research SupportBrazilian Council of Scientific and Technological DevelopmentFoundation for Science and TechnologyAmerican Meteorological Society2020-08-10T12:56:31Z2020-08-10T12:56:31Z2020-08-04Peer-ReviewedPublished versioninfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfSantis, W., Castellanos, P., & Campos, E. (2020). Memory effect of the Southern Atlantic subtropical dipole. Journal of Climate, 33(17), 7679– 7696. https://doi.org/10.1175/JCLI-D-19-0745.11520-0442http://hdl.handle.net/11073/1971410.1175/JCLI-D-19-0745.1en_UShttps://doi.org/10.1175/JCLI-D-19-0745.1oai:repository.aus.edu:11073/197142024-08-22T12:00:25Z
spellingShingle Memory Effect of the Southern Atlantic Subtropical Dipole
Santis, Wlademir
Atmosphere
Ocean
South Atlantic Ocean
Atmosphere-ocean interaction
Entrainment
Mixed layer
status_str publishedVersion
title Memory Effect of the Southern Atlantic Subtropical Dipole
title_full Memory Effect of the Southern Atlantic Subtropical Dipole
title_fullStr Memory Effect of the Southern Atlantic Subtropical Dipole
title_full_unstemmed Memory Effect of the Southern Atlantic Subtropical Dipole
title_short Memory Effect of the Southern Atlantic Subtropical Dipole
title_sort Memory Effect of the Southern Atlantic Subtropical Dipole
topic Atmosphere
Ocean
South Atlantic Ocean
Atmosphere-ocean interaction
Entrainment
Mixed layer
url http://hdl.handle.net/11073/19714