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The role of the South Pacific in modulating Tropical Pacific variability

Tropical Pacific variability (TPV) heavily influences global climate, but much is still unknown about its drivers. We examine the impact of South Pacific variability on the modes of TPV: the El Niño-Southern Oscillation (ENSO) and the Interdecadal Pacific Oscillation (IPO). We conduct idealised coup...

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Autores principales: Chung, Christine T. Y., Power, Scott B., Sullivan, Arnold, Delage, François
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6892857/
https://www.ncbi.nlm.nih.gov/pubmed/31797940
http://dx.doi.org/10.1038/s41598-019-52805-2
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author Chung, Christine T. Y.
Power, Scott B.
Sullivan, Arnold
Delage, François
author_facet Chung, Christine T. Y.
Power, Scott B.
Sullivan, Arnold
Delage, François
author_sort Chung, Christine T. Y.
collection PubMed
description Tropical Pacific variability (TPV) heavily influences global climate, but much is still unknown about its drivers. We examine the impact of South Pacific variability on the modes of TPV: the El Niño-Southern Oscillation (ENSO) and the Interdecadal Pacific Oscillation (IPO). We conduct idealised coupled experiments in which we suppress temperature and salinity variability at all oceanic levels in the South Pacific. This reduces decadal variability in the equatorial Pacific by ~30% and distorts the spatial pattern of the IPO. There is little change to overall interannual variability, however there is a decrease in the magnitude of the largest 5% of both El Niño and La Niña sea-surface temperature (SST) anomalies. Possible reasons for this include: (i) reduced decadal variability means that interannual SST variability is superposed onto a ‘flatter’ background signal, (ii) suppressing South Pacific variability leads to the alteration of coupled processes linking the South and equatorial Pacific. A small but significant mean state change arising from the imposed suppression may also contribute to the weakened extreme ENSO SST anomalies. The magnitude of both extreme El Niño and La Niña SST anomalies are reduced, and the associated spatial patterns of change of upper ocean heat content and wind stress anomalies are markedly different for both types of events.
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spelling pubmed-68928572019-12-10 The role of the South Pacific in modulating Tropical Pacific variability Chung, Christine T. Y. Power, Scott B. Sullivan, Arnold Delage, François Sci Rep Article Tropical Pacific variability (TPV) heavily influences global climate, but much is still unknown about its drivers. We examine the impact of South Pacific variability on the modes of TPV: the El Niño-Southern Oscillation (ENSO) and the Interdecadal Pacific Oscillation (IPO). We conduct idealised coupled experiments in which we suppress temperature and salinity variability at all oceanic levels in the South Pacific. This reduces decadal variability in the equatorial Pacific by ~30% and distorts the spatial pattern of the IPO. There is little change to overall interannual variability, however there is a decrease in the magnitude of the largest 5% of both El Niño and La Niña sea-surface temperature (SST) anomalies. Possible reasons for this include: (i) reduced decadal variability means that interannual SST variability is superposed onto a ‘flatter’ background signal, (ii) suppressing South Pacific variability leads to the alteration of coupled processes linking the South and equatorial Pacific. A small but significant mean state change arising from the imposed suppression may also contribute to the weakened extreme ENSO SST anomalies. The magnitude of both extreme El Niño and La Niña SST anomalies are reduced, and the associated spatial patterns of change of upper ocean heat content and wind stress anomalies are markedly different for both types of events. Nature Publishing Group UK 2019-12-04 /pmc/articles/PMC6892857/ /pubmed/31797940 http://dx.doi.org/10.1038/s41598-019-52805-2 Text en © The Author(s) 2019 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Chung, Christine T. Y.
Power, Scott B.
Sullivan, Arnold
Delage, François
The role of the South Pacific in modulating Tropical Pacific variability
title The role of the South Pacific in modulating Tropical Pacific variability
title_full The role of the South Pacific in modulating Tropical Pacific variability
title_fullStr The role of the South Pacific in modulating Tropical Pacific variability
title_full_unstemmed The role of the South Pacific in modulating Tropical Pacific variability
title_short The role of the South Pacific in modulating Tropical Pacific variability
title_sort role of the south pacific in modulating tropical pacific variability
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6892857/
https://www.ncbi.nlm.nih.gov/pubmed/31797940
http://dx.doi.org/10.1038/s41598-019-52805-2
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