| Abstract: This paper compares various forcings that contribute
to the regional subtidal energetics of the ocean passageway northwest of
Scotland, in the Faroe-Shetland Channel (FSC), where inflow of warm and
saline North Atlantic water mixes with outflow of cold and less-saline
Nordic Sea waters. On the scales resolvable by the (coarse) grid sizes
of delta x = delta y = 20 km and 20 vertical sigma layers, changes
in currents' energetics caused by wind, Atlantic inflow (doubled), decreased
horizontal mixing, surface heat flux, and open-boundary density specifications
were 28, 43, 40, 16, and 5%, respectively, of the kinetic energy of a background
quasi-steady slope current. The subtidal currents were not sensitive to
the atmospheric pressure forcing and the surface relaxation to monthly
climatology nor to the inclusion of additional (apart from M2) tidal constituents
K1, O1, and S2. Wind-induced motions resulted in transport fluctuations
of about 1.5 Sv in the FSC, maximum in winter and minimum in summer, and
alongshore and cross-shore current variances of 0.1 and 0.05 m s-1,
respectively, in fair agreement with observations. Spectral peaks at periods
of 23-30 hours were found and were shown to correspond to resonant continental
shelf waves in the channel. |