Direct numerical simulation of the roll-off range of internal wave shear spectra in the ocean

Oceanic internal gravity waves play an important role in the dynamics of the ocean, providing a link in the overall energy cascade from large forcing scales to small dissipation scales. Quantifying the cascade of energy available for mixing processes in the ocean interior, for example, is essential to accurate modeling of the oceanic general circulation. In the present study, based on an extensive numerical model that resolves most of the internal wave spectrum, the dynamics of the process by which internal waves dissipate their energy in the deep ocean are investigated. Putting all the calculated results together, we propose here a model for the dynamic balance of the internal wave spectrum wherein a downscale energy flux into the high vertical wavenumber near-inertial portion of the spectrum is balanced by energy dissipation at critical layers formed by high vertical wavenumber near-inertial flows.