On the feasibility of using short-range, high-frequency transmissions to characterize the vertical-spectra of small-scale internal waves and turbulence in a bottom boundary layer

Abstract

Using weak fluctuation theory, we examine the detectability of small-scale internal waves and turbulence via short-range, high-frequency transmissions to a vertical array. For internal waves the theory needs modification since the ranges of interest are shorter than the internal wave correlation lengths. The turbulence spectra are characterized by thermal dissipation, χ, kinetic energy dissipation, ε, and outer scale L;0 (largest turbulent eddies) and regions of this space can be explored with different ranges and acoustic frequencies. Very little is known of the internal-wave structure when wave breaking starts. As an example, we consider an experimental arrangement atop the Atlantis 2 seamount where there is a strong, tidally driven boundary layer approximately 100-m thick.