Strong Three-Dimensionality in Nonlinear Internal Waves: Implications for Spatial Coherency, Energy
Abstract
Project Abstract Nonlinear internal waves (NLIWs) are characterized by large amplitudes, strong velocities, and high values of turbulent kinetic energy dissipation. They are a prominent feature of the coastal ocean and play an important role in energy redistribution and mass transport. NLIWs influence a range of natural processes, from nutrient fluxes to sediment transport, and human-based activities, from acoustic wave detection to dispersal of contaminants. Two-dimensional and weakly threedimensional NLIWs have been well studied; however, remote sensing products show that NLIWs are often strongly three-dimensional. Three-dimensionality in NLIWs may represent an important, yet understudied aspect of NLIWs and their effects on the coastal environment and operations. This project proposes to identify and explore the physics that lead to strong three-dimensionality in NLIWs, and to determine the consequences of three-dimensionality to spatial coherence, energy distribution, and mass transport in NLIWs. The proposed work will use analysis of existing data sets, remote sensing, process-oriented modeling, and an optional field component to detail three separate mechanisms that lead to threedimensionality: 1) generation of complex wave forms and multiple wave groups from canyons and headlands, 2) propagation of NLIWs through intense lateral and vertical gradients associated with submesoscale features, and 3) NLIW shoaling over small-scale, abrupt topographic features. This work will address how the above mechanisms lead to three-dimensionality, and whether or not a particular source is likely to dominate in a given region. This work will also assess the time and space scales over which an initially two-dimensional NLIW packet is transformed into a strongly three-dimensional structure, and determine the consequences of spatial coherency in NLIWS to energy distribution and mass transport. The proposed research fits within several of the highlighted interest areas of the Office of Naval Research’s Physical Oceanography program: sub-mesoscale variability associated with fronts, jets, and eddies; internal tides, turbulence, and mixing; and processes that govern ocean mixing and the role of turbulence. The proposed work also aligns with the scope of several underway DRIs including the Submesoscale Dynamics in the South China Sea (SCS-Submesoscale) DRI, the Air-sea Interactions Research Initiative in the Bay of Bengal, and Flow Encountering Rough Topography (FLEAT). Finally, the proposed work is relevant to the Office of Naval Research because it focuses on an energetic, physical feature that both directly impacts coastal operations and needs to be properly parametrized for improvement of predictive model capabilities.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512634
Entities
People
- Emily Lynn Shroyer
Organizations
- Office of Naval Research
- Oregon State University
- United States Navy