Near-Inertial Wave - Mesoscale - Submesoscale Interactions in the North Atlantic Subpolar Gyre
Abstract
1.0 Scope: The proposed study will examine the role of the interactions and energy exchanges between mesoscale eddies, sub-mesoscale currents (SMCs), and near-inertial internal waves (NIWs) in determining global dissipation and mixing patterns in the ocean. The focus of the proposed work is on the fundamental physics that governs the interactions in the North Atlantic Subpolar Gyre, the target location for the Near Inertial Shear and Kinetic Energy in the North Atlantic Experiment(NISKINE). The approach will be to conduct a hierarchy of idealized and realistic state of the art numerical simulations in conjunction with the NISKINE in situ observations for validation The analysis will be based on numerical experiments of variable resolutions that systematically include and exclude wind-forced NIWs. The objectives are 1) to quantify the role of the interactions in making coherent Near-Inertial Oscillations incoherent, thus allowing NIWs to propagate downward from the mixed layer and feed a broad-band internal wave (IW) spectrum or possibly a mixed sub-mesoscale-IW spectrum associated with a stimulated forward cascade, and 2) to determine how mesoscale eddies and SMCs are modified through interactions with NIWs and develop methods to parametrize these wave-induced modifications. 2.0 Requirements: The tasks to be performed are the following: 2.1 Setup realistic simulations in the NISKINE region using the Regional Oceanic Modeling System (ROMS), with appropriate high-frequency wind forcing and multi-level grid nesting of successively finer resolution (_x = 6; 1:5; 0:5; 0:15 km). 2.2 Validate the ROMS solutions against existing and future (NISKINE) observations. Test the sensitivity of the results to the horizontal resolution of the atmospheric wind product. 2.3 Setup idealized simulations using the Large Eddy Simulator Flow Solve, with different stratification, rotation, current strength, and NIW amplitudes, to characterize the NIW-eddy interactions in a wide range of oceanic flow regimes. 2.4 Preform additional realistic ROMS simulations while systematically excluding the forcing components responsible for the generation of NIWs. 2.5 Asses the strength of the NIW-eddy interactions and energy exchanges in the idealized and realistic simulations under the different forcing scenarios, grid resolutions, and parameter regimes. 2.6 Investigate ways to parametrize the effects NIWs have on mesoscale eddies and SMCs using existing and to be developed analytical theories in the idealized solutions. 2.7 Investigate Eulerian- and Lagrangian-based methods to decompose between mesoscale eddies, SMCs, and NIWs in the idealized solutions. 2.8 Apply and test the parametrization and decomposition tools in the realistic solutions. 2.9 Publish findings. 3.0 Deliverables: Reports will be submitted on an annual basis, and a final report will be submitted upon the completion of the award.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 27, 2018
- Source ID
- N000141812697
Entities
People
- Roy Barkan
Organizations
- Office of Naval Research
- United States Navy
- University of California, Los Angeles