Subpolar North Atlantic sea surface salinity as an AMOC mean state indicator

Abstract The Atlantic Meridional Overturning Circulation (AMOC) plays a crucial role in regulating global climate. Although subpolar sea surface temperature (SST) covaries with recent AMOC variability, the relatively short timescales considered by previous studies leave room for doubt on whether sub...

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Main Authors: Jinhui Dai, Fanghua Xu, Jonathon S. Wright, Rui Xin Huang, Xiaomeng Huang
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:npj Climate and Atmospheric Science
Online Access:https://doi.org/10.1038/s41612-025-01190-x
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author Jinhui Dai
Fanghua Xu
Jonathon S. Wright
Rui Xin Huang
Xiaomeng Huang
author_facet Jinhui Dai
Fanghua Xu
Jonathon S. Wright
Rui Xin Huang
Xiaomeng Huang
author_sort Jinhui Dai
collection DOAJ
description Abstract The Atlantic Meridional Overturning Circulation (AMOC) plays a crucial role in regulating global climate. Although subpolar sea surface temperature (SST) covaries with recent AMOC variability, the relatively short timescales considered by previous studies leave room for doubt on whether subpolar SST reliably represents AMOC state. The same doubt arises for the sea surface salinity (SSS), though freshwater flux into the subpolar North Atlantic (SPNA) affects AMOC stability by regulating salinity. Here, we investigate the relationships of SST and SSS with the AMOC mean states in model simulations conducted for paleoclimate modeling. SPNA SSS aligns well with changes in the AMOC mean state under these scenarios, while SST does not. Notably, climate experiments simulating an abrupt quadrupling of CO2 demonstrate a significant correlation between SPNA SSS and transient AMOC strength. The absence of significant SPNA freshening over the past several decades may imply the AMOC is less fragile than previously postulated, but data remain insufficient to predict its long-term stability.
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institution Kabale University
issn 2397-3722
language English
publishDate 2025-08-01
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series npj Climate and Atmospheric Science
spelling doaj-art-e226e3014e2a4e44a5482cd4e7a6bb952025-08-24T11:16:03ZengNature Portfolionpj Climate and Atmospheric Science2397-37222025-08-018111110.1038/s41612-025-01190-xSubpolar North Atlantic sea surface salinity as an AMOC mean state indicatorJinhui Dai0Fanghua Xu1Jonathon S. Wright2Rui Xin Huang3Xiaomeng Huang4Department of Earth System Science, Tsinghua UniversityDepartment of Earth System Science, Tsinghua UniversityDepartment of Earth System Science, Tsinghua UniversityWoods Hole Oceanographic InstitutionDepartment of Earth System Science, Tsinghua UniversityAbstract The Atlantic Meridional Overturning Circulation (AMOC) plays a crucial role in regulating global climate. Although subpolar sea surface temperature (SST) covaries with recent AMOC variability, the relatively short timescales considered by previous studies leave room for doubt on whether subpolar SST reliably represents AMOC state. The same doubt arises for the sea surface salinity (SSS), though freshwater flux into the subpolar North Atlantic (SPNA) affects AMOC stability by regulating salinity. Here, we investigate the relationships of SST and SSS with the AMOC mean states in model simulations conducted for paleoclimate modeling. SPNA SSS aligns well with changes in the AMOC mean state under these scenarios, while SST does not. Notably, climate experiments simulating an abrupt quadrupling of CO2 demonstrate a significant correlation between SPNA SSS and transient AMOC strength. The absence of significant SPNA freshening over the past several decades may imply the AMOC is less fragile than previously postulated, but data remain insufficient to predict its long-term stability.https://doi.org/10.1038/s41612-025-01190-x
spellingShingle Jinhui Dai
Fanghua Xu
Jonathon S. Wright
Rui Xin Huang
Xiaomeng Huang
Subpolar North Atlantic sea surface salinity as an AMOC mean state indicator
npj Climate and Atmospheric Science
title Subpolar North Atlantic sea surface salinity as an AMOC mean state indicator
title_full Subpolar North Atlantic sea surface salinity as an AMOC mean state indicator
title_fullStr Subpolar North Atlantic sea surface salinity as an AMOC mean state indicator
title_full_unstemmed Subpolar North Atlantic sea surface salinity as an AMOC mean state indicator
title_short Subpolar North Atlantic sea surface salinity as an AMOC mean state indicator
title_sort subpolar north atlantic sea surface salinity as an amoc mean state indicator
url https://doi.org/10.1038/s41612-025-01190-x
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