Eddies and a mesoscale deflection of the slope current in the Faroe-Shetland Channel

The mesoscale dynamics of the Scottish side of the Faroe-Shetland Channel h ave been investigated using synoptic in situ and remote sensing observation s. A cold core cyclonic eddy, identified from an AVHRR image, had a diamete r of about 50 km and surface current speeds of up to 50 cm s(-1). it appear ed to be attached to the 800 m isobath as it moved north-eastward along the edge of the channel at about 8 cm s(-1). Speeds in the slope current were about 50 cm s(-1) but increased to 70 cm s(-1) where the current was compre ssed by the eddy. Offshore, over the 1000 m isobath in the cooler water, sp eeds in the current were slower (ca, 20 cm s(-1)). North-west of the Shetla nds the offshore edge of the slope current was deflected across the channel for a distance of about 70 km from the shelf edge. The speed of drifters i n the slope current increased to over 60 cm s(-1) as they moved anti-cyclon ically around this deflection. CTD profiles suggest that the movement of th e surface waters was mirrored in the deep water of the channel. The deflect ion carried a very large quantity of North Atlantic Water into the central part of the channel; its cause and ultimate fate are not known, although it is likely to have had a significant impact on the dynamics of the channel. (C) 1999 Elsevier Science Ltd. All rights reserved.