Three Dimensional Structure of Near-Inertial Waves and Their Interactions with Mesoscale Structures from Direct Observations

Luc Rainville1, James B Girton1, Anna Savage2, Leif N Thomas3 and Caitlin B Whalen1, (1)Applied Physics Laboratory, University of Washington, Seattle, WA, United States, (2)Scripps Institution of Oceanography, La Jolla, CA, United States, (3)Stanford University, Stanford, CA, United States
Near-inertial internal waves are primarily generated by the wind in many places and times across the ocean. Inertial motions interact with other oceanic dynamical structures as they propagate and ultimately form an important component of the global ocean energy balance. The process cruise of the Near-Inertial Shear and Kinetic Energy in the North Atlantic experiment (NISKINe), in June 2019, collected observations with the goal of improving our understanding of the mechanisms that govern the near-inertial response to wind forcing, with a specific focus on how do meso- and submesoscale variability impact generation and propagation of near-inertial internal waves.

The three dimensional structure of near-inertial waves was measured by compact arrays of EM-APEX floats, Wave Gliders, surface Drifters, Slocum gliders, Spray gliders, Seagliders, and a Wirewalker, augmented by intensive ship-based synoptic surveys using the Triaxus, which is a towed undulating profiler. These arrays resolved horizontal scales of the inertial motions of as small as 1 km for several inertial periods at the same time as resolving the mesoscale context and its evolution. In this presentation we contrast the horizontal and vertical wavenumbers of near-inertial oscillations in a relatively quiescent region of the ocean, with that in a region of strong anticyclonic vorticity. This talk will present observations and analyses from several investigators, recognizing intellectual investment and time committed by the entire NISKINe Team.