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Stokes, Euler and Lagrange Aspects of Residual Tidal Transports in the English Channel and the Southern Bight of the North Sea

Published online by Cambridge University Press:  11 May 2009

R. D. Pingree
Affiliation:
N.E.R.C. Institute of Oceanographic Sciences, Brook Road, Wormley, Godalming, Surrey GU8 5UB
Linda Maddock
Affiliation:
The Laboratory, Marine Biological Association, Citadel Hill, Plymouth PL1 2PB

Extract

INTRODUCTION

The dust cart on the Isles of Scilly did not end its service at the local tip, over the cliffs at Deep Point on the eastern side of St Mary's on 14 October 1983. Instead it floated off and continued in service as a Lagrangian drifter, indicating the residual transport of water around the islands. As a hazard to shipping its position was given out as a navigation warning and it was allegedly sighted on the western side of Scilly. The interesting oceanographic question is whether the dust cart was (or would have had it not sunk) circumnavigating the islands in a clockwise or anticlockwise sense. Accordingly this experiment has been repeated using satellite tracked Argos drifting buoys, drogued with parachutes (~ 10 m diameter), and set at depths of about 15 m. The releases showed that the residual transport was clockwise around the islands. In one instance a drogue circumnavigated the islands in about 12 h (i.e. ~ one tidal period) at an average speed of about 100 cm s−1 (Fig. 1).

Type
Research Article
Copyright
Copyright © Marine Biological Association of the United Kingdom 1985

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