New insights into the deep circulation of the Faroe-Shetland channel are gained from a highresolution
regional ocean model. The simulation shows a more complex structure of the deep flow field
than previously thought: a flow reversal of the deep and intermediate waters to the northeast on the Faroese
flank of the channel and persistent topographic eddies that force the deep currents into a gyre-like
structure. This flow reversal opposes the previously accepted understanding of a purely southwestward
deep flow but is in agreement with velocity measurements. The southwestward transport of the overflow
waters is found to be facilitated almost exclusively by a strong and narrow current on the Shetland side of
the channel. Float release experiments show that up to 38% of the overflow water takes longer than a
purely southwestward flow regime suggests and up to 13% takes twice as long. From the release of tracers,
a substantial amount of lateral mixing is evident within the channel, predominantly facilitated by the topographic
eddies.