From Tides to Mixing Along the Hawaiian Ridge

TLDR

The cascade from tides to turbulence has been hypothesized to serve as a major energy pathway for ocean mixing. The study investigated the cascade from tides to turbulence along the Hawaiian Ridge. The investigation employed observations and numerical models to trace the energy pathway. The ridge exhibits a divergence of internal tidal energy flux that matches model predictions, hosts large internal waves up to 300 m, enhances internal‑wave energy, and shows turbulent dissipation ten times higher than open ocean, bringing the energy budget close to closure.

Abstract

The cascade from tides to turbulence has been hypothesized to serve as a major energy pathway for ocean mixing. We investigated this cascade along the Hawaiian Ridge using observations and numerical models. A divergence of internal tidal energy flux observed at the ridge agrees with the predictions of internal tide models. Large internal tidal waves with peak-to-peak amplitudes of up to 300 meters occur on the ridge. Internal-wave energy is enhanced, and turbulent dissipation in the region near the ridge is 10 times larger than open-ocean values. Given these major elements in the tides-to-turbulence cascade, an energy budget approaches closure.