Internal Wave Breaking Dynamics and Associated Mixing in the Coastal Ocean

Abstract

Internal waves are ubiquitous throughout the world's oceans and are generated primarily when the barotropic tides flow over topography and disturb the stratification, thus producing internal tides, or internal waves of tidal frequency. Internal tides propagate over long distances from their generation sites and can steepen into trains of internal solitary waves, thus producing internal waves with wavelengths ranging from over 100km down to 100s of meters. Like surface waves, internal waves break when they encounter topography and are an important component of mixing and transport of heat, salt, sediments, and biological material in the coastal ocean. In this article, we discuss the dynamics of breaking internal waves in the coastal ocean based on a combination of observations and numerical simulations. The breaking and associated mixing and transport of internal tides and internal solitary waves are discussed in the context of the internal Iribarren number, which is a ratio of a measure of the topographic slope to the steepness of the internal wave.