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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Online Access: | http://hdl.handle.net/11073/19714 https://doi.org/10.1175/JCLI-D-19-0745.1 |
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ftamerunishariah:oai:repository.aus.edu:11073/19714 2024-09-30T14:43:38+00:00 Memory Effect of the Southern Atlantic Subtropical Dipole Santis, Wlademir Castellanos, Paola Campos, Edmo 2020-08-04 application/pdf http://hdl.handle.net/11073/19714 https://doi.org/10.1175/JCLI-D-19-0745.1 en_US eng American Meteorological Society https://doi.org/10.1175/JCLI-D-19-0745.1 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 doi:10.1175/JCLI-D-19-0745.1 Atmosphere Ocean South Atlantic Ocean Atmosphere-ocean interaction Entrainment Mixed layer Peer-Reviewed Article Published version 2020 ftamerunishariah https://doi.org/10.1175/JCLI-D-19-0745.1 2024-09-13T08:54:23Z 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. São Paulo State Foundation for Research Support Brazilian Council of Scientific and Technological Development Foundation for Science and Technology Article in Journal/Newspaper South Atlantic Ocean DSpace at AUS (American University of Sharjah) Austral Journal of Climate 33 17 7679 7696 |
institution |
Open Polar |
collection |
DSpace at AUS (American University of Sharjah) |
op_collection_id |
ftamerunishariah |
language |
English |
topic |
Atmosphere Ocean South Atlantic Ocean Atmosphere-ocean interaction Entrainment Mixed layer |
spellingShingle |
Atmosphere Ocean South Atlantic Ocean Atmosphere-ocean interaction Entrainment Mixed layer Santis, Wlademir Castellanos, Paola Campos, Edmo Memory Effect of the Southern Atlantic Subtropical Dipole |
topic_facet |
Atmosphere Ocean South Atlantic Ocean Atmosphere-ocean interaction Entrainment Mixed layer |
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. São Paulo State Foundation for Research Support Brazilian Council of Scientific and Technological Development Foundation for Science and Technology |
format |
Article in Journal/Newspaper |
author |
Santis, Wlademir Castellanos, Paola Campos, Edmo |
author_facet |
Santis, Wlademir Castellanos, Paola Campos, Edmo |
author_sort |
Santis, Wlademir |
title |
Memory Effect of the Southern Atlantic Subtropical Dipole |
title_short |
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_sort |
memory effect of the southern atlantic subtropical dipole |
publisher |
American Meteorological Society |
publishDate |
2020 |
url |
http://hdl.handle.net/11073/19714 https://doi.org/10.1175/JCLI-D-19-0745.1 |
geographic |
Austral |
geographic_facet |
Austral |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_relation |
https://doi.org/10.1175/JCLI-D-19-0745.1 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 doi:10.1175/JCLI-D-19-0745.1 |
op_doi |
https://doi.org/10.1175/JCLI-D-19-0745.1 |
container_title |
Journal of Climate |
container_volume |
33 |
container_issue |
17 |
container_start_page |
7679 |
op_container_end_page |
7696 |
_version_ |
1811645357332889600 |