Is there evidence of changes in Tropical Atlantic Variability modes under AMO phases in the observational record?

Is there evidence of changes in Tropical Atlantic Variability modes under AMO phases in the... AbstractThe Atlantic Multidecadal Oscillation (AMO) is the leading mode of Atlantic Sea Surface Temperature (SST) variability at multidecadal time-scales. Previous studies have denoted that AMO could modulate El Niño-Southern Oscillation (ENSO) variance. However, the role played by 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 inter-annual 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-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-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, denoted as Horse-Shoe (HS) pattern, 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. Our results give a step forward in the better understanding of TAV, which is essential to improve its modelling, impacts and predictability. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Climate American Meteorological Society

Is there evidence of changes in Tropical Atlantic Variability modes under AMO phases in the observational record?

Loading next page...
 
/lp/ams/is-there-evidence-of-changes-in-tropical-atlantic-variability-modes-e0lGgGtYhg
Publisher
American Meteorological Society
Copyright
Copyright © American Meteorological Society
ISSN
1520-0442
D.O.I.
10.1175/JCLI-D-16-0459.1
Publisher site
See Article on Publisher Site

Abstract

AbstractThe Atlantic Multidecadal Oscillation (AMO) is the leading mode of Atlantic Sea Surface Temperature (SST) variability at multidecadal time-scales. Previous studies have denoted that AMO could modulate El Niño-Southern Oscillation (ENSO) variance. However, the role played by 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 inter-annual 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-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-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, denoted as Horse-Shoe (HS) pattern, 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. Our results give a step forward in the better understanding of TAV, which is essential to improve its modelling, impacts and predictability.

Journal

Journal of ClimateAmerican Meteorological Society

Published: Jun 28, 2017

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve Freelancer

DeepDyve Pro

Price
FREE
$49/month

$360/year
Save searches from
Google Scholar,
PubMed
Create lists to
organize your research
Export lists, citations
Read DeepDyve articles
Abstract access only
Unlimited access to over
18 million full-text articles
Print
20 pages/month
PDF Discount
20% off