1147 / 2024-09-20 15:12:17

Enhanced Abyssal Turbulent Mixing in Submarine Canyons

submarine canyons,dissipation,internal tides,topography,mixing

Internal tides are a type of internal waves with tidal frequencies that are ubiquitous in global oceans. A portion of the internal tidal energy dissipates locally near its generation site, while the remainder propagates outward as low-mode internal tides. The interaction of low-mode internal tides with topography facilitates wave breaking and drives turbulence, enhancing abyssal mixing. Previous theoretical models and numerical simulations have predominantly concentrated on large-scale topographic features. However, a recent geological survey uncovered a fine-scale submarine canyon group in the South China Sea, which had not been detected by existing high-resolution topographic data. Additionally, the scarcity of field observational data has left the dynamical characteristics of the region largely unresolved. Our study, grounded in observational and model data, examined the energy dissipation dynamics within this submarine canyon group. The findings reveal that the internal tides in this region are predominantly composed of those originating from the Luzon Strait, alongside locally generated internal tides. The influence of the Luzon Strait internal tides is primarily confined to the upper ocean layers, exerting minimal impact on the deeper waters. The dissipation dynamics within the canyon group region are predominantly governed by its intricate topography, indicating a significant intensification of abyssal mixing around these topographic features.