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Changes in wave climate over the northwest European shelf seas during the last 12,000 years

Neil, S.P., Scourse, J.D., Bigg, G.R. and Uehara, K. (2009) Changes in wave climate over the northwest European shelf seas during the last 12,000 years. Journal of Geophysical Research (All Series), 114. C06015. ISSN 0148-0227

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Abstract

Because of the depth attenuation of wave orbital velocity, wave-induced bed shear stress is much more sensitive to changes in total water depth than tidal-induced bed shear stress. The ratio between wave- and tidal-induced bed shear stress in many shelf sea regions has varied considerably over the recent geological past because of combined eustatic changes in sea level and isostatic adjustment. In order to capture the high-frequency nature of wind events, a two-dimensional spectral wave model is here applied at high temporal resolution to time slices from 12 ka BP to present using paleobathymetries of the NW European shelf seas. By contrasting paleowave climates and bed shear stress distributions with present-day conditions, the model results demonstrate that, in regions of the shelf seas that remained wet continuously over the last 12,000 years, annual root-mean-square (rms) and peak wave heights increased from 12 ka BP to present. This increase in wave height was accompanied by a large reduction in the annual rms wave- induced bed shear stress, primarily caused by a reduction in the magnitude of wave orbital velocity penetrating to the bed for increasing relative sea level. In regions of the shelf seas which remained wet over the last 12,000 years, the annual mean ratio of wave- to (M-2) tidal-induced bed shear stress decreased from 1 (at 12 ka BP) to its present-day value of 0.5. Therefore compared to present- day conditions, waves had a more important contribution to large-scale sediment transport processes in the Celtic Sea and the northwestern North Sea at 12 ka BP.

Item Type: Article
Copyright, Publisher and Additional Information: An edited version of this paper was published by AGU. Copyright 2009 American Geophysical Union
Keywords: Induced sand transport; level change; glacial maximum; Irish sea; continental shelf; coastal regions; holocene tides; British Isles; water depth; ice sheets
Institution: The University of Sheffield
Academic Units: The University of Sheffield > Faculty of Social Sciences (Sheffield) > Department of Geography (Sheffield)
Depositing User: Miss Anthea Tucker
Date Deposited: 23 Jul 2009 11:26
Last Modified: 15 Sep 2014 01:34
Published Version: http://dx.doi.org/10.1029/2009JC005288
Status: Published
Publisher: American Geophysical Union
Refereed: Yes
Identification Number: 10.1029/2009JC005288
URI: http://eprints.whiterose.ac.uk/id/eprint/9011

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