23 / 2026-05-09 20:32:23

A numerical study of tides in the Ross Sea: eddy-like structures, bottom trapped waves, and energetics

Session 60 - Polar Ice Sheet-Shelf-Ocean Processes, Changes, and Sea Level Implications

Using a high-resolution numerical model with tidal decomposition and energy diagnostics, this study investigates tide-topography interactions, energy conversions, and tide-induced cross-slope exchange in the Ross Sea. The decomposed topographic mode, generated as diurnal surface-mode flows impinge on the Ross Sea slope, exhibits three eddy-like structures along the slope. This occurs because the divergence and convergence of diurnal surface-mode tidal flows generate sea surface height extremes, which persist longer than the time required for geostrophic adjustment, allowing rotating geostrophic flows to develop around them. The topographic mode dominates the water exchange across the slope and yields a net heat transport towards the shelf (~12 TW). The surface and topographic modes can exchange energy with each other, as indicated by alternating positive and negative patches of energy conversion rate with a magnitude reaching 1 W/m². The baroclinic tides in the Ross Sea manifest as bottom-trapped waves over the continental slope and other topographic gradients. The energy of baroclinic tides, primarily converted from the surface mode, is an order of magnitude smaller than the barotropic tides. The barotropic component accounts for most of the tidal dissipation along the slope (~0.1 W/m²), with a minimal contribution from baroclinic tides. This study identifies tides as an important driver of heat transport onto the Antarctic shelf, which is fundamental for accurately predicting Antarctic ice shelf melt and global sea level rise.