On sea level change in the North Sea influenced by the North Atlantic Oscillation: Local and remote steric effects
On sea level change in the North Sea influenced by the North Atlantic Oscillation: Local and remote steric effects
In this study, contributions of both local steric and remote baroclinic effects (i.e., steric variations external to the region of interest) to the inter-annual variability of winter sea level in the North Sea, with respect to the North Atlantic Oscillation (NAO), for the period of 1953–2010 are investigated. On inter-annual time scales in this period, the NAO is significantly correlated to sea level variations in the North Sea only in the winter months (December–March), while its correlation to sea temperature over much of the North Sea is only significant in January and February. The discrepancy in sea level between observations and barotropic tide and surge models forced by tides and local atmospheric forcing, i.e., local atmospheric pressure effects and winds, in the present study are found to be consistent with previous studies. In the North Sea, local thermosteric effects caused by thermal expansion play a minor role on winter-mean NAO related sea level variability compared with atmospheric forcing. This is particularly true in the southeastern North Sea where water depths are mostly less than 25 m. Our calculations demonstrate that the discrepancy can be mostly explained by remote baroclinic effects, which appear as water mass exchanges on the continental shelf and are therefore only apparent in ocean bottom pressure. In the North Sea, NAO related sea level variations seem to be a hybrid of barotropic and baroclinic processes. Hence, they can only be adequately modelled with three-dimensional baroclinic ocean models that include contributions of baroclinic effects and large-scale atmospheric forcing external to the region of interest.
North Sea, sea level, North Atlantic Oscillation, steric effect, baroclinic effect
186-195
Chen, Xinping
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Dangendorf, Sönke
ba1c5cbe-a385-41dc-8a46-da8cd36cf19d
Narayan, Nikesh
5dd5d61e-6ed6-4b75-a449-e84fcdb91115
O'Driscoll, Kieran
037023aa-6f67-47e3-b4b0-b0733d9d8e74
Tsimplis, Michael N.
df6dd749-cda4-46ec-983c-bf022d737031
Su, Jian
3779ae69-14a6-45c8-a934-ef719ef185d7
Mayer, Bernhard
9f9f3f54-ff56-4b0b-b098-87bd25004c7f
Pohlmann, Thomas
59fa5890-01b8-46cc-a56e-4c34e010fc74
4 December 2014
Chen, Xinping
3167c5cc-f039-488d-899e-e91b247da45e
Dangendorf, Sönke
ba1c5cbe-a385-41dc-8a46-da8cd36cf19d
Narayan, Nikesh
5dd5d61e-6ed6-4b75-a449-e84fcdb91115
O'Driscoll, Kieran
037023aa-6f67-47e3-b4b0-b0733d9d8e74
Tsimplis, Michael N.
df6dd749-cda4-46ec-983c-bf022d737031
Su, Jian
3779ae69-14a6-45c8-a934-ef719ef185d7
Mayer, Bernhard
9f9f3f54-ff56-4b0b-b098-87bd25004c7f
Pohlmann, Thomas
59fa5890-01b8-46cc-a56e-4c34e010fc74
Chen, Xinping, Dangendorf, Sönke, Narayan, Nikesh, O'Driscoll, Kieran, Tsimplis, Michael N., Su, Jian, Mayer, Bernhard and Pohlmann, Thomas
(2014)
On sea level change in the North Sea influenced by the North Atlantic Oscillation: Local and remote steric effects.
Estuarine, Coastal and Shelf Science, 151, .
(doi:10.1016/j.ecss.2014.10.009).
Abstract
In this study, contributions of both local steric and remote baroclinic effects (i.e., steric variations external to the region of interest) to the inter-annual variability of winter sea level in the North Sea, with respect to the North Atlantic Oscillation (NAO), for the period of 1953–2010 are investigated. On inter-annual time scales in this period, the NAO is significantly correlated to sea level variations in the North Sea only in the winter months (December–March), while its correlation to sea temperature over much of the North Sea is only significant in January and February. The discrepancy in sea level between observations and barotropic tide and surge models forced by tides and local atmospheric forcing, i.e., local atmospheric pressure effects and winds, in the present study are found to be consistent with previous studies. In the North Sea, local thermosteric effects caused by thermal expansion play a minor role on winter-mean NAO related sea level variability compared with atmospheric forcing. This is particularly true in the southeastern North Sea where water depths are mostly less than 25 m. Our calculations demonstrate that the discrepancy can be mostly explained by remote baroclinic effects, which appear as water mass exchanges on the continental shelf and are therefore only apparent in ocean bottom pressure. In the North Sea, NAO related sea level variations seem to be a hybrid of barotropic and baroclinic processes. Hence, they can only be adequately modelled with three-dimensional baroclinic ocean models that include contributions of baroclinic effects and large-scale atmospheric forcing external to the region of interest.
Text
Chen_manuscript_resubmit_05.pdf
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Published date: 4 December 2014
Keywords:
North Sea, sea level, North Atlantic Oscillation, steric effect, baroclinic effect
Organisations:
Marine Physics and Ocean Climate
Identifiers
Local EPrints ID: 373087
URI: http://eprints.soton.ac.uk/id/eprint/373087
ISSN: 0272-7714
PURE UUID: 100a43c5-e8f7-40ae-8773-910bb618a0b2
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Date deposited: 05 Jan 2015 17:16
Last modified: 14 Mar 2024 18:47
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Contributors
Author:
Xinping Chen
Author:
Sönke Dangendorf
Author:
Nikesh Narayan
Author:
Kieran O'Driscoll
Author:
Michael N. Tsimplis
Author:
Jian Su
Author:
Bernhard Mayer
Author:
Thomas Pohlmann
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