Sub-tidal dynamics of a near-coastal zone in the North Sea
van Haren, J.J.M. (1990). Sub-tidal dynamics of a near-coastal zone in the North Sea. Neth. J. Sea Res. 25(1-2): 31-44
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, more
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Abstract |
Data, gathered in the North Sea some 60 km north of the Netherlands, are used to describe the regional dynamics at sub-tidal frequencies. Using a tidally averaged set of the vertically averaged horizontal momentum equations, the influence of the separate terms in these equations is investigated experimentally. The results reveal that, especially further offshore, the wind driven motion is in (near) geostrophic balance. This confirms the ability to monitor the circulation, using information on the wind field and the bottom pressure distribution, within an accuracy equivalent to an accuracy of 0.5 mb of low pass filtered bottom pressure gauge measurements. In a part of the area where the bottom topography reaches a slope of 1.2x10-3 and where density fronts are observed, the motion is frequently found out of geostrophic balance. The apparent imbalance can partly be attributed to 'sub-grid' horizontal density gradients, which are incorporated in the measured bottom pressure gradients, assuming that no sea-level adjustment occurs. |
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