Decoupled Freshwater Transport and Meridional Overturning in the South Atlantic
Abstract Freshwater transports (Fov) by the Atlantic meridional overturning circulation (AMOC) are sensitive to salinity distributions and may determine AMOC stability. However, climate models show large salinity biases, distorting the relation between Fov and the AMOC. Using free‐running models and...
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ftdoajarticles:oai:doaj.org/article:a545cbcfa66548d39b078427182df1a7 2024-09-15T17:48:20+00:00 Decoupled Freshwater Transport and Meridional Overturning in the South Atlantic D. Mignac D. Ferreira K. Haines 2019-02-01T00:00:00Z https://doi.org/10.1029/2018GL081328 https://doaj.org/article/a545cbcfa66548d39b078427182df1a7 EN eng Wiley https://doi.org/10.1029/2018GL081328 https://doaj.org/toc/0094-8276 https://doaj.org/toc/1944-8007 1944-8007 0094-8276 doi:10.1029/2018GL081328 https://doaj.org/article/a545cbcfa66548d39b078427182df1a7 Geophysical Research Letters, Vol 46, Iss 4, Pp 2178-2186 (2019) AMOC overturning gyre AAIW ocean reanalyses bistability Geophysics. Cosmic physics QC801-809 article 2019 ftdoajarticles https://doi.org/10.1029/2018GL081328 2024-08-05T17:49:10Z Abstract Freshwater transports (Fov) by the Atlantic meridional overturning circulation (AMOC) are sensitive to salinity distributions and may determine AMOC stability. However, climate models show large salinity biases, distorting the relation between Fov and the AMOC. Using free‐running models and ocean reanalyses with realistic salinities but quite different AMOCs, we show that the fresh Antarctic Intermediate Water layer eliminates salinity differences across the AMOC branches at ~1,200 m, ∆S1200m, which decouples Fov from the AMOC south of ~10°N. As the Antarctic Intermediate Water disappears north of ~10°N, a large ∆S1200m allows the AMOC to drive substantial southward Fov in the North Atlantic. In the South Atlantic the 0–300 m zonal salinity contrasts control the gyre freshwater transports Fgyre, which also determine the total freshwater transports. This decoupling makes the southern Fov unlikely to play any role in AMOC stability, leaving indirect Fgyre feedbacks or Fov in the north, as more relevant factors. Article in Journal/Newspaper Antarc* Antarctic North Atlantic Directory of Open Access Journals: DOAJ Articles Geophysical Research Letters 46 4 2178 2186 |
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Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
AMOC overturning gyre AAIW ocean reanalyses bistability Geophysics. Cosmic physics QC801-809 |
spellingShingle |
AMOC overturning gyre AAIW ocean reanalyses bistability Geophysics. Cosmic physics QC801-809 D. Mignac D. Ferreira K. Haines Decoupled Freshwater Transport and Meridional Overturning in the South Atlantic |
topic_facet |
AMOC overturning gyre AAIW ocean reanalyses bistability Geophysics. Cosmic physics QC801-809 |
description |
Abstract Freshwater transports (Fov) by the Atlantic meridional overturning circulation (AMOC) are sensitive to salinity distributions and may determine AMOC stability. However, climate models show large salinity biases, distorting the relation between Fov and the AMOC. Using free‐running models and ocean reanalyses with realistic salinities but quite different AMOCs, we show that the fresh Antarctic Intermediate Water layer eliminates salinity differences across the AMOC branches at ~1,200 m, ∆S1200m, which decouples Fov from the AMOC south of ~10°N. As the Antarctic Intermediate Water disappears north of ~10°N, a large ∆S1200m allows the AMOC to drive substantial southward Fov in the North Atlantic. In the South Atlantic the 0–300 m zonal salinity contrasts control the gyre freshwater transports Fgyre, which also determine the total freshwater transports. This decoupling makes the southern Fov unlikely to play any role in AMOC stability, leaving indirect Fgyre feedbacks or Fov in the north, as more relevant factors. |
format |
Article in Journal/Newspaper |
author |
D. Mignac D. Ferreira K. Haines |
author_facet |
D. Mignac D. Ferreira K. Haines |
author_sort |
D. Mignac |
title |
Decoupled Freshwater Transport and Meridional Overturning in the South Atlantic |
title_short |
Decoupled Freshwater Transport and Meridional Overturning in the South Atlantic |
title_full |
Decoupled Freshwater Transport and Meridional Overturning in the South Atlantic |
title_fullStr |
Decoupled Freshwater Transport and Meridional Overturning in the South Atlantic |
title_full_unstemmed |
Decoupled Freshwater Transport and Meridional Overturning in the South Atlantic |
title_sort |
decoupled freshwater transport and meridional overturning in the south atlantic |
publisher |
Wiley |
publishDate |
2019 |
url |
https://doi.org/10.1029/2018GL081328 https://doaj.org/article/a545cbcfa66548d39b078427182df1a7 |
genre |
Antarc* Antarctic North Atlantic |
genre_facet |
Antarc* Antarctic North Atlantic |
op_source |
Geophysical Research Letters, Vol 46, Iss 4, Pp 2178-2186 (2019) |
op_relation |
https://doi.org/10.1029/2018GL081328 https://doaj.org/toc/0094-8276 https://doaj.org/toc/1944-8007 1944-8007 0094-8276 doi:10.1029/2018GL081328 https://doaj.org/article/a545cbcfa66548d39b078427182df1a7 |
op_doi |
https://doi.org/10.1029/2018GL081328 |
container_title |
Geophysical Research Letters |
container_volume |
46 |
container_issue |
4 |
container_start_page |
2178 |
op_container_end_page |
2186 |
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1810289482653499392 |