Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record?
The Atlantic multidecadal oscillation (AMO) is the leading mode of Atlantic sea surface temperature (SST) variability at multidecadal time scales. Previous studies have shown that the AMO could modulate El Niño–Southern Oscillation (ENSO) variance. However, the role played by the AMO in the tropical...
Published in: | Journal of Climate |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Meteorological Society
2018
|
Subjects: | |
Online Access: | https://centaur.reading.ac.uk/75463/ https://centaur.reading.ac.uk/75463/1/jcli-d-16-0459.1.pdf |
id |
ftunivreading:oai:centaur.reading.ac.uk:75463 |
---|---|
record_format |
openpolar |
spelling |
ftunivreading:oai:centaur.reading.ac.uk:75463 2024-06-23T07:55:15+00:00 Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record? Martín-Rey, Marta Polo, Irene Rodríguez-Fonseca, Belén Losada, Teresa Lazar, Alban 2018-01 text https://centaur.reading.ac.uk/75463/ https://centaur.reading.ac.uk/75463/1/jcli-d-16-0459.1.pdf en eng American Meteorological Society https://centaur.reading.ac.uk/75463/1/jcli-d-16-0459.1.pdf Martín-Rey, M., Polo, I. <https://centaur.reading.ac.uk/view/creators/90004825.html>, Rodríguez-Fonseca, B., Losada, T. and Lazar, A. (2018) Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record? Journal of Climate, 31 (2). pp. 515-536. ISSN 1520-0442 doi: https://doi.org/10.1175/jcli-d-16-0459.1 <https://doi.org/10.1175/jcli-d-16-0459.1> Article PeerReviewed 2018 ftunivreading 2024-06-11T15:07:33Z The Atlantic multidecadal oscillation (AMO) is the leading mode of Atlantic sea surface temperature (SST) variability at multidecadal time scales. Previous studies have shown that the AMO could modulate El Niño–Southern Oscillation (ENSO) variance. However, the role played by the AMO in the tropical Atlantic variability (TAV) is still uncertain. Here, it is demonstrated that during negative AMO phases, associated with a shallower thermocline, the eastern equatorial Atlantic SST variability is enhanced by more than 150% in boreal summer. Consequently, the interannual TAV modes are modified. During negative AMO, the Atlantic Niño displays larger amplitude and a westward extension and it is preceded by a simultaneous weakening of both subtropical highs in winter and spring. In contrast, a meridional seesaw SLP pattern evolving into a zonal gradient leads the Atlantic Niño during positive AMO. The north tropical Atlantic (NTA) mode is related to a Scandinavian blocking pattern during winter and spring in negative AMO, while under positive AMO it is part of the SST tripole associated with the North Atlantic Oscillation. Interestingly, the emergence of an overlooked variability mode, here called the horseshoe (HS) pattern on account of its shape, is favored during negative AMO. This anomalous warm (cool) HS surrounding an eastern equatorial cooling (warming) is remotely forced by an ENSO phenomenon. During negative AMO, the tropical–extratropical teleconnections are enhanced and the Walker circulation is altered. This, together with the increased equatorial SST variability, could promote the ENSO impacts on TAV. The results herein give a step forward in the better understanding of TAV, which is essential to improving its modeling, impacts, and predictability. Article in Journal/Newspaper North Atlantic North Atlantic oscillation CentAUR: Central Archive at the University of Reading Journal of Climate 31 2 515 536 |
institution |
Open Polar |
collection |
CentAUR: Central Archive at the University of Reading |
op_collection_id |
ftunivreading |
language |
English |
description |
The Atlantic multidecadal oscillation (AMO) is the leading mode of Atlantic sea surface temperature (SST) variability at multidecadal time scales. Previous studies have shown that the AMO could modulate El Niño–Southern Oscillation (ENSO) variance. However, the role played by the AMO in the tropical Atlantic variability (TAV) is still uncertain. Here, it is demonstrated that during negative AMO phases, associated with a shallower thermocline, the eastern equatorial Atlantic SST variability is enhanced by more than 150% in boreal summer. Consequently, the interannual TAV modes are modified. During negative AMO, the Atlantic Niño displays larger amplitude and a westward extension and it is preceded by a simultaneous weakening of both subtropical highs in winter and spring. In contrast, a meridional seesaw SLP pattern evolving into a zonal gradient leads the Atlantic Niño during positive AMO. The north tropical Atlantic (NTA) mode is related to a Scandinavian blocking pattern during winter and spring in negative AMO, while under positive AMO it is part of the SST tripole associated with the North Atlantic Oscillation. Interestingly, the emergence of an overlooked variability mode, here called the horseshoe (HS) pattern on account of its shape, is favored during negative AMO. This anomalous warm (cool) HS surrounding an eastern equatorial cooling (warming) is remotely forced by an ENSO phenomenon. During negative AMO, the tropical–extratropical teleconnections are enhanced and the Walker circulation is altered. This, together with the increased equatorial SST variability, could promote the ENSO impacts on TAV. The results herein give a step forward in the better understanding of TAV, which is essential to improving its modeling, impacts, and predictability. |
format |
Article in Journal/Newspaper |
author |
Martín-Rey, Marta Polo, Irene Rodríguez-Fonseca, Belén Losada, Teresa Lazar, Alban |
spellingShingle |
Martín-Rey, Marta Polo, Irene Rodríguez-Fonseca, Belén Losada, Teresa Lazar, Alban Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record? |
author_facet |
Martín-Rey, Marta Polo, Irene Rodríguez-Fonseca, Belén Losada, Teresa Lazar, Alban |
author_sort |
Martín-Rey, Marta |
title |
Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record? |
title_short |
Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record? |
title_full |
Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record? |
title_fullStr |
Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record? |
title_full_unstemmed |
Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record? |
title_sort |
is there evidence of changes in tropical atlantic variability modes under amo phases in the observational record? |
publisher |
American Meteorological Society |
publishDate |
2018 |
url |
https://centaur.reading.ac.uk/75463/ https://centaur.reading.ac.uk/75463/1/jcli-d-16-0459.1.pdf |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
https://centaur.reading.ac.uk/75463/1/jcli-d-16-0459.1.pdf Martín-Rey, M., Polo, I. <https://centaur.reading.ac.uk/view/creators/90004825.html>, Rodríguez-Fonseca, B., Losada, T. and Lazar, A. (2018) Is there evidence of changes in tropical Atlantic variability modes under AMO phases in the observational record? Journal of Climate, 31 (2). pp. 515-536. ISSN 1520-0442 doi: https://doi.org/10.1175/jcli-d-16-0459.1 <https://doi.org/10.1175/jcli-d-16-0459.1> |
container_title |
Journal of Climate |
container_volume |
31 |
container_issue |
2 |
container_start_page |
515 |
op_container_end_page |
536 |
_version_ |
1802647767160455168 |