Quantifying Patterns of Internal Wave Properties and Turbulence over the Inner Shelf
Abstract
Between the surf zone and the deeper, the inner shelf is the stratified region where turbulent surface and bottom boundary layers co,mprise a substantial portion of the water column, separated by a spatially and temporally variable, stratified region in between. In,ner shelf dynamics are influenced both by low-frequency wind-driven currents and high-frequency processes, including highly energeti,c internal waves and turbulence. The vertical distributions of buoyancy and momentum within the inner shelf are largely determined b,y turbulent fluxes, which are driven by high-frequency processes but have a significant aggregate impact on low-frequency flows thro,ugh changes in stratification and effective turbulent viscosity. Much of the turbulence is driven by nonlinear internal tides that e,volve significantly as they propagate across the shelf into shallow water. These nonlinear internal waves (NLIWs) are modulated by t,he background stratification and currents, which evolve significantly on synoptic to seasonal timescales. The complex interactions c,onnecting low-frequency dynamics, stratification, currents, high-frequency internal wave evolution, and magnitude and vertical struc,ture of turbulence make it challenging to obtain a simple closure of inner shelf dynamics. Here we propose to explore these intercon,nected inner shelf dynamics through a focused analysis of a recently collected dataset of unprecedented scope. This project will uti,lize the highly resolved ISDE observations to elucidate how low-frequency currents and stratification on the inner self both impact, and are impacted by internal waves through the generation of turbulent dissipation. There are 3 distinct aims. In Part I, we will e,valuate the combined influence of background currents and stratification on the cross-shelf evolution of internal tides. In Part II,, we will identify the variability of the vertical structure of turbulence throughout the shelf and determine the leading mechanisms, of turbulence generation that underlie these patterns. Part III uses an event-scale analysis of wave characteristics and vertical s,tructures of turbulence to assess how variability in the internal wave field ultimately impacts the feedback on the shelf. Collectiv,ely, these analyses will clarify the contribution of internal tides to low-frequency inner shelf conditions and inform the improved, parameterization of these inter-connected dynamics in numerical models. This abstract is publicly releasable.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 16, 2022
- Source ID
- N000142212399
Entities
People
- Amy F. Waterhouse
Organizations
- Office of Naval Research
- United States Navy
- University of California, San Diego