Pantropical Indo-Atlantic temperature gradient modulates multi-decadal AMOC variability in models and observations

Abstract Interconnections between ocean basins are recognized as an important driver of climate variability. Recent modeling evidence suggests that the North Atlantic climate can respond to persistent warming of the tropical Indian Ocean sea surface temperature (SST) relative to the rest of the trop...

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Published in:npj Climate and Atmospheric Science
Main Authors: Brady S. Ferster, Leonard F. Borchert, Juliette Mignot, Matthew B. Menary, Christophe Cassou, Alexey V. Fedorov
Format: Article in Journal/Newspaper
Language:English
Published: Nature Portfolio 2023
Subjects:
Online Access:https://doi.org/10.1038/s41612-023-00489-x
https://doaj.org/article/8549e717339a4d8195de6b8bfba9853b
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spelling ftdoajarticles:oai:doaj.org/article:8549e717339a4d8195de6b8bfba9853b 2023-11-12T04:21:52+01:00 Pantropical Indo-Atlantic temperature gradient modulates multi-decadal AMOC variability in models and observations Brady S. Ferster Leonard F. Borchert Juliette Mignot Matthew B. Menary Christophe Cassou Alexey V. Fedorov 2023-10-01T00:00:00Z https://doi.org/10.1038/s41612-023-00489-x https://doaj.org/article/8549e717339a4d8195de6b8bfba9853b EN eng Nature Portfolio https://doi.org/10.1038/s41612-023-00489-x https://doaj.org/toc/2397-3722 doi:10.1038/s41612-023-00489-x 2397-3722 https://doaj.org/article/8549e717339a4d8195de6b8bfba9853b npj Climate and Atmospheric Science, Vol 6, Iss 1, Pp 1-8 (2023) Environmental sciences GE1-350 Meteorology. Climatology QC851-999 article 2023 ftdoajarticles https://doi.org/10.1038/s41612-023-00489-x 2023-10-29T00:42:08Z Abstract Interconnections between ocean basins are recognized as an important driver of climate variability. Recent modeling evidence suggests that the North Atlantic climate can respond to persistent warming of the tropical Indian Ocean sea surface temperature (SST) relative to the rest of the tropics (rTIO). Here, we use observational data to demonstrate that multi-decadal changes in pantropical ocean temperature gradients lead to variations of an SST-based proxy of the Atlantic Meridional Overturning Circulation (AMOC). The largest contribution to this temperature gradient-AMOC connection comes from gradients between the Indian and Atlantic Oceans. The rTIO index yields the strongest connection of this tropical temperature gradient to the AMOC. Focusing on the internally generated signal in three observational products reveals that an SST-based AMOC proxy index has closely followed low-frequency changes of rTIO temperature with about 26-year lag since 1870. Analyzing the pre-industrial control simulations of 44 CMIP6 climate models shows that the AMOC proxy index lags simulated mid-latitude AMOC variations by 4 ± 4 years. These model simulations reveal the mechanism connecting AMOC variations to pantropical ocean temperature gradients at a 27 ± 2 years lag, matching the observed time lag in 28 out of the 44 analyzed models. rTIO temperature changes affect the North Atlantic climate through atmospheric planetary waves, impacting temperature and salinity in the subpolar North Atlantic, which modifies deep convection and ultimately the AMOC. Through this mechanism, observed internal rTIO variations can serve as a multi-decadal precursor of AMOC changes with important implications for AMOC dynamics and predictability. Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles npj Climate and Atmospheric Science 6 1
institution Open Polar
collection Directory of Open Access Journals: DOAJ Articles
op_collection_id ftdoajarticles
language English
topic Environmental sciences
GE1-350
Meteorology. Climatology
QC851-999
spellingShingle Environmental sciences
GE1-350
Meteorology. Climatology
QC851-999
Brady S. Ferster
Leonard F. Borchert
Juliette Mignot
Matthew B. Menary
Christophe Cassou
Alexey V. Fedorov
Pantropical Indo-Atlantic temperature gradient modulates multi-decadal AMOC variability in models and observations
topic_facet Environmental sciences
GE1-350
Meteorology. Climatology
QC851-999
description Abstract Interconnections between ocean basins are recognized as an important driver of climate variability. Recent modeling evidence suggests that the North Atlantic climate can respond to persistent warming of the tropical Indian Ocean sea surface temperature (SST) relative to the rest of the tropics (rTIO). Here, we use observational data to demonstrate that multi-decadal changes in pantropical ocean temperature gradients lead to variations of an SST-based proxy of the Atlantic Meridional Overturning Circulation (AMOC). The largest contribution to this temperature gradient-AMOC connection comes from gradients between the Indian and Atlantic Oceans. The rTIO index yields the strongest connection of this tropical temperature gradient to the AMOC. Focusing on the internally generated signal in three observational products reveals that an SST-based AMOC proxy index has closely followed low-frequency changes of rTIO temperature with about 26-year lag since 1870. Analyzing the pre-industrial control simulations of 44 CMIP6 climate models shows that the AMOC proxy index lags simulated mid-latitude AMOC variations by 4 ± 4 years. These model simulations reveal the mechanism connecting AMOC variations to pantropical ocean temperature gradients at a 27 ± 2 years lag, matching the observed time lag in 28 out of the 44 analyzed models. rTIO temperature changes affect the North Atlantic climate through atmospheric planetary waves, impacting temperature and salinity in the subpolar North Atlantic, which modifies deep convection and ultimately the AMOC. Through this mechanism, observed internal rTIO variations can serve as a multi-decadal precursor of AMOC changes with important implications for AMOC dynamics and predictability.
format Article in Journal/Newspaper
author Brady S. Ferster
Leonard F. Borchert
Juliette Mignot
Matthew B. Menary
Christophe Cassou
Alexey V. Fedorov
author_facet Brady S. Ferster
Leonard F. Borchert
Juliette Mignot
Matthew B. Menary
Christophe Cassou
Alexey V. Fedorov
author_sort Brady S. Ferster
title Pantropical Indo-Atlantic temperature gradient modulates multi-decadal AMOC variability in models and observations
title_short Pantropical Indo-Atlantic temperature gradient modulates multi-decadal AMOC variability in models and observations
title_full Pantropical Indo-Atlantic temperature gradient modulates multi-decadal AMOC variability in models and observations
title_fullStr Pantropical Indo-Atlantic temperature gradient modulates multi-decadal AMOC variability in models and observations
title_full_unstemmed Pantropical Indo-Atlantic temperature gradient modulates multi-decadal AMOC variability in models and observations
title_sort pantropical indo-atlantic temperature gradient modulates multi-decadal amoc variability in models and observations
publisher Nature Portfolio
publishDate 2023
url https://doi.org/10.1038/s41612-023-00489-x
https://doaj.org/article/8549e717339a4d8195de6b8bfba9853b
genre North Atlantic
genre_facet North Atlantic
op_source npj Climate and Atmospheric Science, Vol 6, Iss 1, Pp 1-8 (2023)
op_relation https://doi.org/10.1038/s41612-023-00489-x
https://doaj.org/toc/2397-3722
doi:10.1038/s41612-023-00489-x
2397-3722
https://doaj.org/article/8549e717339a4d8195de6b8bfba9853b
op_doi https://doi.org/10.1038/s41612-023-00489-x
container_title npj Climate and Atmospheric Science
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