The Application of Internal-Wave Dissipation Models to a Region of Strong Mixing

Abstract

Several models now exist for predicting the dissipation rate of turbulent kinetic energy, ε, in the oceanic thermocline as a function of the large-scale properties of the internal gravity wave field. These models are based on the transfer of energy toward smaller vertical scales by wave-wave interactions, and their predictions are typically evaluated for a canonical internal wave field as described by Garrett and Munk. Much of the total oceanic dissipation may occur, however, in regions where the wave field deviates in some way from the canonical form. In this paper simultaneous measurements of the internal wave field and ε from a drifting ice camp in the eastern Arctic Ocean are used to evaluate the efficacy of existing models in a region with an anomalous wave field and energetic mixing. By explicitly retaining the vertical wavenumber bandwidth parameter, β*, models can still provide reasonable estimates of the dissipation rate. The amount of data required to estimate β*, is, however, substantially greater than for cases where the canonical vertical wavenumber spectrum can be assumed.