Buoyancy forcing: a key driver of northern North Atlantic sea surface temperature variability across multiple timescales
Analyses of observational data (from year 1870 AD) show that sea surface temperature (SST) anomalies along the pathway of Atlantic Water transport in the North Atlantic, the Norwegian Sea and the Iceland Sea are spatially coherent at multidecadal timescales. Spatially coherent SST anomalies are also...
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Online Access: | https://doi.org/10.5194/cp-19-1101-2023 https://cp.copernicus.org/articles/19/1101/2023/ |
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ftcopernicus:oai:publications.copernicus.org:cp106613 2023-06-18T03:41:18+02:00 Buoyancy forcing: a key driver of northern North Atlantic sea surface temperature variability across multiple timescales Risebrobakken, Bjørg Jensen, Mari F. Langehaug, Helene R. Eldevik, Tor Sandø, Anne Britt Li, Camille Born, Andreas McClymont, Erin Louise Salzmann, Ulrich Schepper, Stijn 2023-06-01 application/pdf https://doi.org/10.5194/cp-19-1101-2023 https://cp.copernicus.org/articles/19/1101/2023/ eng eng doi:10.5194/cp-19-1101-2023 https://cp.copernicus.org/articles/19/1101/2023/ eISSN: 1814-9332 Text 2023 ftcopernicus https://doi.org/10.5194/cp-19-1101-2023 2023-06-05T16:24:03Z Analyses of observational data (from year 1870 AD) show that sea surface temperature (SST) anomalies along the pathway of Atlantic Water transport in the North Atlantic, the Norwegian Sea and the Iceland Sea are spatially coherent at multidecadal timescales. Spatially coherent SST anomalies are also observed over hundreds of thousands of years during parts of the Pliocene (5.23–5.03, 4.63–4.43, and 4.33–4.03 Ma). However, when investigating CMIP6 (Coupled Model Intercomparison Project 6) SSP126 (Shared Socioeconomic Pathway) future scenario runs (next century) and other Pliocene time intervals, the following three additional SST relations emerge: (1) the Norwegian Sea SST anomaly is dissimilar to the North Atlantic and the Iceland Sea SST anomalies (Pliocene; 4.93–4.73 and 3.93–3.63 Ma), (2) the Iceland Sea SST anomaly is dissimilar to the North Atlantic and the Norwegian Sea SST anomalies (Pliocene; 3.43–3.23 Ma), and (3) the North Atlantic SST anomaly is dissimilar to the SST anomalies of the Norwegian and Iceland seas (future trend). Hence, spatially non-coherent SST anomalies may occur in equilibrium climates (Pliocene), as well as in response to transient forcing (CMIP6 SSP126 low-emission future scenario). Since buoyancy is a key forcing for the inflow of Atlantic Water to the Norwegian Sea, we investigate the impacts of buoyancy forcing on spatial relations between SST anomalies seen in the North Atlantic and the Norwegian and Iceland seas. This is done by performing a range of idealized experiments using the Massachusetts Institute of Technology general circulation model (MITgcm). Through these idealized experiments we can reproduce three out of four of the documented SST anomaly relations: being spatially coherent under weak to intermediate freshwater forcing over the Nordic Seas, the Iceland Sea being dissimilar to the North Atlantic and the Norwegian Sea under weak atmospheric warming over the Nordic Seas, and the North Atlantic being dissimilar to the Norwegian and Iceland seas under strong ... Text Iceland Nordic Seas North Atlantic Norwegian Sea Copernicus Publications: E-Journals Norwegian Sea Climate of the Past 19 5 1101 1123 |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
Analyses of observational data (from year 1870 AD) show that sea surface temperature (SST) anomalies along the pathway of Atlantic Water transport in the North Atlantic, the Norwegian Sea and the Iceland Sea are spatially coherent at multidecadal timescales. Spatially coherent SST anomalies are also observed over hundreds of thousands of years during parts of the Pliocene (5.23–5.03, 4.63–4.43, and 4.33–4.03 Ma). However, when investigating CMIP6 (Coupled Model Intercomparison Project 6) SSP126 (Shared Socioeconomic Pathway) future scenario runs (next century) and other Pliocene time intervals, the following three additional SST relations emerge: (1) the Norwegian Sea SST anomaly is dissimilar to the North Atlantic and the Iceland Sea SST anomalies (Pliocene; 4.93–4.73 and 3.93–3.63 Ma), (2) the Iceland Sea SST anomaly is dissimilar to the North Atlantic and the Norwegian Sea SST anomalies (Pliocene; 3.43–3.23 Ma), and (3) the North Atlantic SST anomaly is dissimilar to the SST anomalies of the Norwegian and Iceland seas (future trend). Hence, spatially non-coherent SST anomalies may occur in equilibrium climates (Pliocene), as well as in response to transient forcing (CMIP6 SSP126 low-emission future scenario). Since buoyancy is a key forcing for the inflow of Atlantic Water to the Norwegian Sea, we investigate the impacts of buoyancy forcing on spatial relations between SST anomalies seen in the North Atlantic and the Norwegian and Iceland seas. This is done by performing a range of idealized experiments using the Massachusetts Institute of Technology general circulation model (MITgcm). Through these idealized experiments we can reproduce three out of four of the documented SST anomaly relations: being spatially coherent under weak to intermediate freshwater forcing over the Nordic Seas, the Iceland Sea being dissimilar to the North Atlantic and the Norwegian Sea under weak atmospheric warming over the Nordic Seas, and the North Atlantic being dissimilar to the Norwegian and Iceland seas under strong ... |
format |
Text |
author |
Risebrobakken, Bjørg Jensen, Mari F. Langehaug, Helene R. Eldevik, Tor Sandø, Anne Britt Li, Camille Born, Andreas McClymont, Erin Louise Salzmann, Ulrich Schepper, Stijn |
spellingShingle |
Risebrobakken, Bjørg Jensen, Mari F. Langehaug, Helene R. Eldevik, Tor Sandø, Anne Britt Li, Camille Born, Andreas McClymont, Erin Louise Salzmann, Ulrich Schepper, Stijn Buoyancy forcing: a key driver of northern North Atlantic sea surface temperature variability across multiple timescales |
author_facet |
Risebrobakken, Bjørg Jensen, Mari F. Langehaug, Helene R. Eldevik, Tor Sandø, Anne Britt Li, Camille Born, Andreas McClymont, Erin Louise Salzmann, Ulrich Schepper, Stijn |
author_sort |
Risebrobakken, Bjørg |
title |
Buoyancy forcing: a key driver of northern North Atlantic sea surface temperature variability across multiple timescales |
title_short |
Buoyancy forcing: a key driver of northern North Atlantic sea surface temperature variability across multiple timescales |
title_full |
Buoyancy forcing: a key driver of northern North Atlantic sea surface temperature variability across multiple timescales |
title_fullStr |
Buoyancy forcing: a key driver of northern North Atlantic sea surface temperature variability across multiple timescales |
title_full_unstemmed |
Buoyancy forcing: a key driver of northern North Atlantic sea surface temperature variability across multiple timescales |
title_sort |
buoyancy forcing: a key driver of northern north atlantic sea surface temperature variability across multiple timescales |
publishDate |
2023 |
url |
https://doi.org/10.5194/cp-19-1101-2023 https://cp.copernicus.org/articles/19/1101/2023/ |
geographic |
Norwegian Sea |
geographic_facet |
Norwegian Sea |
genre |
Iceland Nordic Seas North Atlantic Norwegian Sea |
genre_facet |
Iceland Nordic Seas North Atlantic Norwegian Sea |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-19-1101-2023 https://cp.copernicus.org/articles/19/1101/2023/ |
op_doi |
https://doi.org/10.5194/cp-19-1101-2023 |
container_title |
Climate of the Past |
container_volume |
19 |
container_issue |
5 |
container_start_page |
1101 |
op_container_end_page |
1123 |
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1769006806631186432 |