Teleconnections and relationship between the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) in reconstructions and models over the past millennium
The climate of the Southern Hemisphere (SH) is strongly influenced by variations in the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). Because of the limited length of instrumental records in most parts of the SH, very little is known about the relationship between these tw...
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ftcopernicus:oai:publications.copernicus.org:cp79784 2023-05-15T13:24:07+02:00 Teleconnections and relationship between the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) in reconstructions and models over the past millennium Dätwyler, Christoph Grosjean, Martin Steiger, Nathan J. Neukom, Raphael 2020-04-22 application/pdf https://doi.org/10.5194/cp-16-743-2020 https://cp.copernicus.org/articles/16/743/2020/ eng eng doi:10.5194/cp-16-743-2020 https://cp.copernicus.org/articles/16/743/2020/ eISSN: 1814-9332 Text 2020 ftcopernicus https://doi.org/10.5194/cp-16-743-2020 2020-07-20T16:22:15Z The climate of the Southern Hemisphere (SH) is strongly influenced by variations in the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). Because of the limited length of instrumental records in most parts of the SH, very little is known about the relationship between these two key modes of variability over time. Using proxy-based reconstructions and last-millennium climate model simulations, we find that ENSO and SAM indices are mostly negatively correlated over the past millennium. Pseudo-proxy experiments indicate that currently available proxy records are able to reliably capture ENSO–SAM relationships back to at least 1600 CE. Palaeoclimate reconstructions show mostly negative correlations back to about 1400 CE. An ensemble of last-millennium climate model simulations confirms this negative correlation, showing a stable correlation of approximately −0.3 . Despite this generally negative relationship we do find intermittent periods of positive ENSO–SAM correlations in individual model simulations and in the palaeoclimate reconstructions. We do not find evidence that these relationship fluctuations are caused by exogenous forcing nor by a consistent climate pattern. However, we do find evidence that strong negative correlations are associated with strong positive (negative) anomalies in the Interdecadal Pacific Oscillation and the Amundsen Sea Low during periods when SAM and ENSO indices are of opposite (equal) sign. Text Amundsen Sea Copernicus Publications: E-Journals Amundsen Sea Pacific Climate of the Past 16 2 743 756 |
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Copernicus Publications: E-Journals |
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English |
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The climate of the Southern Hemisphere (SH) is strongly influenced by variations in the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). Because of the limited length of instrumental records in most parts of the SH, very little is known about the relationship between these two key modes of variability over time. Using proxy-based reconstructions and last-millennium climate model simulations, we find that ENSO and SAM indices are mostly negatively correlated over the past millennium. Pseudo-proxy experiments indicate that currently available proxy records are able to reliably capture ENSO–SAM relationships back to at least 1600 CE. Palaeoclimate reconstructions show mostly negative correlations back to about 1400 CE. An ensemble of last-millennium climate model simulations confirms this negative correlation, showing a stable correlation of approximately −0.3 . Despite this generally negative relationship we do find intermittent periods of positive ENSO–SAM correlations in individual model simulations and in the palaeoclimate reconstructions. We do not find evidence that these relationship fluctuations are caused by exogenous forcing nor by a consistent climate pattern. However, we do find evidence that strong negative correlations are associated with strong positive (negative) anomalies in the Interdecadal Pacific Oscillation and the Amundsen Sea Low during periods when SAM and ENSO indices are of opposite (equal) sign. |
format |
Text |
author |
Dätwyler, Christoph Grosjean, Martin Steiger, Nathan J. Neukom, Raphael |
spellingShingle |
Dätwyler, Christoph Grosjean, Martin Steiger, Nathan J. Neukom, Raphael Teleconnections and relationship between the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) in reconstructions and models over the past millennium |
author_facet |
Dätwyler, Christoph Grosjean, Martin Steiger, Nathan J. Neukom, Raphael |
author_sort |
Dätwyler, Christoph |
title |
Teleconnections and relationship between the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) in reconstructions and models over the past millennium |
title_short |
Teleconnections and relationship between the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) in reconstructions and models over the past millennium |
title_full |
Teleconnections and relationship between the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) in reconstructions and models over the past millennium |
title_fullStr |
Teleconnections and relationship between the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) in reconstructions and models over the past millennium |
title_full_unstemmed |
Teleconnections and relationship between the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) in reconstructions and models over the past millennium |
title_sort |
teleconnections and relationship between the el niño–southern oscillation (enso) and the southern annular mode (sam) in reconstructions and models over the past millennium |
publishDate |
2020 |
url |
https://doi.org/10.5194/cp-16-743-2020 https://cp.copernicus.org/articles/16/743/2020/ |
geographic |
Amundsen Sea Pacific |
geographic_facet |
Amundsen Sea Pacific |
genre |
Amundsen Sea |
genre_facet |
Amundsen Sea |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-16-743-2020 https://cp.copernicus.org/articles/16/743/2020/ |
op_doi |
https://doi.org/10.5194/cp-16-743-2020 |
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Climate of the Past |
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16 |
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2 |
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743 |
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756 |
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