Mechanisms of decadal changes in sea surface height and heat content in the eastern Nordic Seas
The Nordic Seas constitute the main ocean conveyor of heat between the North Atlantic Ocean and the Arctic Ocean. Although the decadal variability in the subpolar North Atlantic has been given significant attention lately, especially regarding the cooling trend since the mid-2000s, less is known abo...
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ftcopernicus:oai:publications.copernicus.org:os80528 2023-05-15T15:13:11+02:00 Mechanisms of decadal changes in sea surface height and heat content in the eastern Nordic Seas Broomé, Sara Chafik, Léon Nilsson, Johan 2020-06-15 application/pdf https://doi.org/10.5194/os-16-715-2020 https://os.copernicus.org/articles/16/715/2020/ eng eng doi:10.5194/os-16-715-2020 https://os.copernicus.org/articles/16/715/2020/ eISSN: 1812-0792 Text 2020 ftcopernicus https://doi.org/10.5194/os-16-715-2020 2020-07-20T16:22:06Z The Nordic Seas constitute the main ocean conveyor of heat between the North Atlantic Ocean and the Arctic Ocean. Although the decadal variability in the subpolar North Atlantic has been given significant attention lately, especially regarding the cooling trend since the mid-2000s, less is known about the potential connection downstream in the northern basins. Using sea surface heights from satellite altimetry over the past 25 years (1993–2017), we find significant variability on multiyear to decadal timescales in the Nordic Seas. In particular, the regional trends in sea surface height show signs of a weakening since the mid-2000s, as compared to the rapid increase in the preceding decade since the early 1990s. This change is most prominent in the Atlantic origin waters in the eastern Nordic Seas and is closely linked, as estimated from hydrography, to heat content. Furthermore, we formulate a simple heat budget for the eastern Nordic Seas to discuss the relative importance of local and remote sources of variability; advection of temperature anomalies in the Atlantic inflow is found to be the main mechanism. A conceptual model of ocean heat convergence, with only upstream temperature measurements at the inflow to the Nordic Seas as input, is able to reproduce key aspects of the decadal variability in the heat content of the Nordic Seas. Based on these results, we argue that there is a strong connection with the upstream subpolar North Atlantic. However, although the shift in trends in the mid-2000s is coincident in the Nordic Seas and the subpolar North Atlantic, the eastern Nordic Seas have not seen a reversal of trends but instead maintain elevated sea surface heights and heat content in the recent decade considered here. Text Arctic Arctic Ocean Nordic Seas North Atlantic Copernicus Publications: E-Journals Arctic Arctic Ocean Ocean Science 16 3 715 728 |
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Copernicus Publications: E-Journals |
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English |
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The Nordic Seas constitute the main ocean conveyor of heat between the North Atlantic Ocean and the Arctic Ocean. Although the decadal variability in the subpolar North Atlantic has been given significant attention lately, especially regarding the cooling trend since the mid-2000s, less is known about the potential connection downstream in the northern basins. Using sea surface heights from satellite altimetry over the past 25 years (1993–2017), we find significant variability on multiyear to decadal timescales in the Nordic Seas. In particular, the regional trends in sea surface height show signs of a weakening since the mid-2000s, as compared to the rapid increase in the preceding decade since the early 1990s. This change is most prominent in the Atlantic origin waters in the eastern Nordic Seas and is closely linked, as estimated from hydrography, to heat content. Furthermore, we formulate a simple heat budget for the eastern Nordic Seas to discuss the relative importance of local and remote sources of variability; advection of temperature anomalies in the Atlantic inflow is found to be the main mechanism. A conceptual model of ocean heat convergence, with only upstream temperature measurements at the inflow to the Nordic Seas as input, is able to reproduce key aspects of the decadal variability in the heat content of the Nordic Seas. Based on these results, we argue that there is a strong connection with the upstream subpolar North Atlantic. However, although the shift in trends in the mid-2000s is coincident in the Nordic Seas and the subpolar North Atlantic, the eastern Nordic Seas have not seen a reversal of trends but instead maintain elevated sea surface heights and heat content in the recent decade considered here. |
format |
Text |
author |
Broomé, Sara Chafik, Léon Nilsson, Johan |
spellingShingle |
Broomé, Sara Chafik, Léon Nilsson, Johan Mechanisms of decadal changes in sea surface height and heat content in the eastern Nordic Seas |
author_facet |
Broomé, Sara Chafik, Léon Nilsson, Johan |
author_sort |
Broomé, Sara |
title |
Mechanisms of decadal changes in sea surface height and heat content in the eastern Nordic Seas |
title_short |
Mechanisms of decadal changes in sea surface height and heat content in the eastern Nordic Seas |
title_full |
Mechanisms of decadal changes in sea surface height and heat content in the eastern Nordic Seas |
title_fullStr |
Mechanisms of decadal changes in sea surface height and heat content in the eastern Nordic Seas |
title_full_unstemmed |
Mechanisms of decadal changes in sea surface height and heat content in the eastern Nordic Seas |
title_sort |
mechanisms of decadal changes in sea surface height and heat content in the eastern nordic seas |
publishDate |
2020 |
url |
https://doi.org/10.5194/os-16-715-2020 https://os.copernicus.org/articles/16/715/2020/ |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Nordic Seas North Atlantic |
genre_facet |
Arctic Arctic Ocean Nordic Seas North Atlantic |
op_source |
eISSN: 1812-0792 |
op_relation |
doi:10.5194/os-16-715-2020 https://os.copernicus.org/articles/16/715/2020/ |
op_doi |
https://doi.org/10.5194/os-16-715-2020 |
container_title |
Ocean Science |
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16 |
container_issue |
3 |
container_start_page |
715 |
op_container_end_page |
728 |
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1766343776356270080 |