The barotropic and baroclinic tides in the Ross Sea were simulated using a primitive equation, sigma-coordinate model, the Regional Ocean Model System (ROMS), for four tidal constituents, M2, S2, K1, and O1. Small elevation amplitudes were predicted over most of the basin, with a combined standard deviation of 30–50 cm. Larger amplitudes, with standard deviations ranging from 50–70 cm, occurred deep within the ice shelf cavity, over the continental slope, and over Iselin Bank. Most of the elevation response was associated with the diurnal constituents (K1 and O1), as was most of the depth-independent (barotropic) velocity response. Baroclinic tides were generated at locations of steep topography for the semidiurnal constituents, but not the diurnal. Diurnal continental shelf waves were generated by the diurnal tides and found to amplify the semidiurnal elevations and baroclinic tidal velocities over the continental slope. Comparisons with observations in both elevation and velocities showed very good agreement for the semidiurnal constituents (M2 and S2) and moderate agreement for the diurnal constituents (K1 and O1). The disagreement for the diurnal constituents was associated with diurnal frequency continental shelf waves, which were overexcited along the shelf break. The baroclinic tides induced both small-scale horizontal and vertical shear in the velocity fields in the Ross Sea.

In certain regions of the Southern Ocean, tidal energy is believed to foster the mixing of different water masses, which eventually contribute to the formation of deep and bottom waters. The Ross Sea is one of the major ventilation sites of the global ocean abyss and a region of sparse tidal observations. We investigated M2 tidal dynamics in the Ross Sea using a three-dimensional sigma coordinate model, the Regional Ocean Model System (ROMS). Realistic topography and hydrography from existing observational data were used with a single tidal constituent, the semi-diurnal M2. The model fields faithfully reproduced the major features of the tidal circulation and had reasonable agreement with ten existing tidal elevation observations and forty-two existing tidal current measurements. The differences were attributed primarily to topographic errors. Internal tides were generated at the continental shelf/slope break and other areas of steep topography. Strong vertical shears in the horizontal velocities occurred under and at the edges of the Ross Ice Shelf and along the continental shelf/slope break. Estimates of lead formation based on divergence of baroclinic velocities were significantly higher than those based on barotrophic velocities, reaching over 10% at the continental shelf/slope break.