NISKINE: Profiling Float Measurements of Near-Inertial Waves and Turbulence
Abstract
An array of 15 EM-APEX floats were deployed in northern Atlantic to investigate near-inertial waves modulated by mesoscale eddy field and to study seasonal variability of turbulence mixing driven by near-inertial waves and internal tides. Strong refraction of near-inertial waves by mesoscale vorticity gradient was observed and compared with theoretical results. In late summer through early spring, near-inertial/semidiurnal motions were energized in the surface mixed-layer and permanent pycnocline penetrated to 800-m after late summer and fall storms. Internal-wave vertical shear variance was tilde 5 times as energetic as canonical midlatitude (GM) internal waves. Clockwise-with-depth (downward energy propagation) shear dominates over this same period while counterclockwise-with-depth (upward energy propagation) shear dominates in late spring and early summer, and is correlated with major topographic ridges. Turbulent diapycnal diffusivities are tilde 10-4 m2 s-1, an order of magnitude larger than the canonical mid-latitude and exhibit factor-of-three month-to-month variability, consistent with the elevated internal-wave shear.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 04, 2024
- Accession Number
- AD1225413
Entities
People
- Caitlin Whalen
- James Girton
- Ren-Chieh Lien
Organizations
- University of Washington