SUBTIDAL ENERGETICS IN THE FAROE-SHETLAND CHANNEL - COARSE-GRID MODELEXPERIMENT

This paper compares various forcings that contribute to the regional s ubtidal energetics of the ocean passageway northwest of Scotland, in t he 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 horizo ntal mixing, surface heat flux, and open-boundary density specificatio ns were 28, 43, 40, 16, and 5%, respectively, of the kinetic energy of a background quasi-steady slope current. The subtidal currents were n ot sensitive to the atmospheric pressure forcing and the surface relax ation to monthly climatology nor to the inclusion of additional (apart from M2) tidal constituents K1, O1, and S2. Wind-induced motions resu lted in transport fluctuations of about 1.5 Sv in the FSC, maximum in winter and minimum in summer, and alongshore and cross-shore current v ariances 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 c hannel.