Separation of Internal Waves and Vortical Motions: Analysis of LatMix EM-APEX Float Measurements
Abstract
Separation of Internal Waves and Vortical Motions: Analysis of LatMix ?-EM-APEX Float Measurements In unprecedented amount, detail and quality, we have observed the small and sub-mesoscale structure of the ocean on horizontal scales from 100 m to 10 km. The effort was in conjunction with the Scalable Lateral Mixing and Coherent Turbulence DRI (aka LatMix). We collected over 9,000 profiles of V, S and T with a swarm of twenty EM-APEX floats (Sanford et al. 2007) profiling to 150 m simultaneously. Ten floats also measured microstructure fluctuations in temperature, which are used to estimate turbulent vertical diffusivity and dissipation rate of turbulent kinetic energy. This is a new approach toward observing oceanic submesoscale property and kinetic variations, and is a game changer in this field. The existence of the smallscale vortical mode at the same time and spatial scales of internal waves was recognized nearly 30 years ago (Müller 1984, Müller et al. 1986). Its importance to the enstrophy and energy cascades and to lateral mixing was suggested by previous studies. Unfortunately, the small-scale vortical mode has not been quantified due to the lack of adequate measurements. The 3-D measurements taken by the swarm of EM-APEX floats during LatMix provide the first opportunity for quantifying the small-scale vortical mode energy, its frequency and wavenumber characteristics and its contribution to the lateral dispersion and mixing. This proposal represents a break-through study of oceanic small-scale and sub-mesoscale processes. Our unique observations may be essential to revealing the vorticity structure and its importance in this intermediate scale domain.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512184
Entities
People
- Ren-Chieh Lien
Organizations
- Office of Naval Research
- United States Navy
- University of Washington