Variability along the Atlantic water pathway in the forced Norwegian Earth System Model
The growing attention on mechanisms that can provide predictability on interannual-to-decadal time scales, makes it necessary to identify how well climate models represent such mechanisms. In this study we use a high (0.25° horizontal grid) and a medium (1°) resolution version of a forced global oce...
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Language: | English |
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2018
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Online Access: | https://hdl.handle.net/1956/19229 https://doi.org/10.1007/s00382-018-4184-5 |
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ftunivbergen:oai:bora.uib.no:1956/19229 2023-05-15T17:24:19+02:00 Variability along the Atlantic water pathway in the forced Norwegian Earth System Model Langehaug, Helene R. Sandø, Anne Britt Årthun, Marius Ilicak, Mehmet 2018-07-19T13:18:21Z application/pdf text/xml https://hdl.handle.net/1956/19229 https://doi.org/10.1007/s00382-018-4184-5 eng eng Springer Berlin Heidelberg EC/H2020: 727852 Norges forskningsråd: 263223 Norges forskningsråd: 229774 EC/FP7: 610055 EC/FP7: 308299 Norges forskningsråd: 229763 urn:issn:0930-7575 urn:issn:1432-0894 https://hdl.handle.net/1956/19229 https://doi.org/10.1007/s00382-018-4184-5 cristin:1583674 Attribution CC BY http://creativecommons.org/licenses/by/4.0/ Copyright The Author(s) 2018 Climate Dynamics Thermohaline anomalies Atlantic water Subpolar North Atlantic Nordic seas Subpolar Gyre NorESM Peer reviewed Journal article 2018 ftunivbergen https://doi.org/10.1007/s00382-018-4184-5 2023-03-14T17:38:46Z The growing attention on mechanisms that can provide predictability on interannual-to-decadal time scales, makes it necessary to identify how well climate models represent such mechanisms. In this study we use a high (0.25° horizontal grid) and a medium (1°) resolution version of a forced global ocean-sea ice model, utilising the Norwegian Earth System Model, to assess the impact of increased ocean resolution. Our target is the simulation of temperature and salinity anomalies along the pathway of warm Atlantic water in the subpolar North Atlantic and the Nordic Seas. Although the high resolution version has larger biases in general at the ocean surface, the poleward propagation of thermohaline anomalies is better resolved in this version, i.e., the time for an anomaly to travel northward is more similar to observation based estimates. The extent of these anomalies can be rather large in both model versions, as also seen in observations, e.g., stretching from Scotland to northern Norway. The easternmost branch into the Nordic and Barents Seas, carrying warm Atlantic water, is also improved by higher resolution, both in terms of mean heat transport and variability in thermohaline properties. A more detailed assessment of the link between the North Atlantic Ocean circulation and the thermohaline anomalies at the entrance of the Nordic Seas reveals that the high resolution is more consistent with mechanisms that are previously published. This suggests better dynamics and variability in the subpolar region and the Nordic Seas in the high resolution compared to the medium resolution. This is most likely due a better representation of the mean circulation in the studied region when using higher resolution. As the poleward propagation of ocean heat anomalies is considered to be a key source of climate predictability, we recommend that similar methodology presented herein should be performed on coupled climate models that are used for climate prediction. publishedVersion Article in Journal/Newspaper Nordic Seas North Atlantic Northern Norway Sea ice University of Bergen: Bergen Open Research Archive (BORA-UiB) Norway Climate Dynamics 52 1-2 1211 1230 |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
Thermohaline anomalies Atlantic water Subpolar North Atlantic Nordic seas Subpolar Gyre NorESM |
spellingShingle |
Thermohaline anomalies Atlantic water Subpolar North Atlantic Nordic seas Subpolar Gyre NorESM Langehaug, Helene R. Sandø, Anne Britt Årthun, Marius Ilicak, Mehmet Variability along the Atlantic water pathway in the forced Norwegian Earth System Model |
topic_facet |
Thermohaline anomalies Atlantic water Subpolar North Atlantic Nordic seas Subpolar Gyre NorESM |
description |
The growing attention on mechanisms that can provide predictability on interannual-to-decadal time scales, makes it necessary to identify how well climate models represent such mechanisms. In this study we use a high (0.25° horizontal grid) and a medium (1°) resolution version of a forced global ocean-sea ice model, utilising the Norwegian Earth System Model, to assess the impact of increased ocean resolution. Our target is the simulation of temperature and salinity anomalies along the pathway of warm Atlantic water in the subpolar North Atlantic and the Nordic Seas. Although the high resolution version has larger biases in general at the ocean surface, the poleward propagation of thermohaline anomalies is better resolved in this version, i.e., the time for an anomaly to travel northward is more similar to observation based estimates. The extent of these anomalies can be rather large in both model versions, as also seen in observations, e.g., stretching from Scotland to northern Norway. The easternmost branch into the Nordic and Barents Seas, carrying warm Atlantic water, is also improved by higher resolution, both in terms of mean heat transport and variability in thermohaline properties. A more detailed assessment of the link between the North Atlantic Ocean circulation and the thermohaline anomalies at the entrance of the Nordic Seas reveals that the high resolution is more consistent with mechanisms that are previously published. This suggests better dynamics and variability in the subpolar region and the Nordic Seas in the high resolution compared to the medium resolution. This is most likely due a better representation of the mean circulation in the studied region when using higher resolution. As the poleward propagation of ocean heat anomalies is considered to be a key source of climate predictability, we recommend that similar methodology presented herein should be performed on coupled climate models that are used for climate prediction. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Langehaug, Helene R. Sandø, Anne Britt Årthun, Marius Ilicak, Mehmet |
author_facet |
Langehaug, Helene R. Sandø, Anne Britt Årthun, Marius Ilicak, Mehmet |
author_sort |
Langehaug, Helene R. |
title |
Variability along the Atlantic water pathway in the forced Norwegian Earth System Model |
title_short |
Variability along the Atlantic water pathway in the forced Norwegian Earth System Model |
title_full |
Variability along the Atlantic water pathway in the forced Norwegian Earth System Model |
title_fullStr |
Variability along the Atlantic water pathway in the forced Norwegian Earth System Model |
title_full_unstemmed |
Variability along the Atlantic water pathway in the forced Norwegian Earth System Model |
title_sort |
variability along the atlantic water pathway in the forced norwegian earth system model |
publisher |
Springer Berlin Heidelberg |
publishDate |
2018 |
url |
https://hdl.handle.net/1956/19229 https://doi.org/10.1007/s00382-018-4184-5 |
geographic |
Norway |
geographic_facet |
Norway |
genre |
Nordic Seas North Atlantic Northern Norway Sea ice |
genre_facet |
Nordic Seas North Atlantic Northern Norway Sea ice |
op_source |
Climate Dynamics |
op_relation |
EC/H2020: 727852 Norges forskningsråd: 263223 Norges forskningsråd: 229774 EC/FP7: 610055 EC/FP7: 308299 Norges forskningsråd: 229763 urn:issn:0930-7575 urn:issn:1432-0894 https://hdl.handle.net/1956/19229 https://doi.org/10.1007/s00382-018-4184-5 cristin:1583674 |
op_rights |
Attribution CC BY http://creativecommons.org/licenses/by/4.0/ Copyright The Author(s) 2018 |
op_doi |
https://doi.org/10.1007/s00382-018-4184-5 |
container_title |
Climate Dynamics |
container_volume |
52 |
container_issue |
1-2 |
container_start_page |
1211 |
op_container_end_page |
1230 |
_version_ |
1766115276711002112 |