Turbulent length scales in a fast-flowing, weakly stratified, strait: Cook Strait, New Zealand
oleh: C. L. Stevens, C. L. Stevens
| Format: | Article |
|---|---|
| Diterbitkan: | Copernicus Publications 2018-08-01 |
Deskripsi
<p>There remains much to be learned about the full range of turbulent motions in the ocean. Here we consider turbulence and overturn scales in the relatively shallow, weakly stratified, fast-flowing tidal flows of Cook Strait, New Zealand. With flow speeds reaching 3 m s<sup>−1</sup> in a water column of ∼ 300 m depth the location is heuristically known to be highly turbulent. Dissipation rates of turbulent kinetic energy <i>ε</i>, along with the Thorpe scale, <i>L</i><sub>T</sub>, are described. Thorpe scales, often as much as one-quarter of the water depth, are compared with dissipation rates and background flow speed. Turbulent energy dissipation rates <i>ε</i> are modest but high for oceans, around 5×10<sup>−5</sup> W kg<sup>−1</sup>. Comparison of the buoyancy-limit Ozmidov scale <i>L</i><sub>Oz</sub> suggest the Cook Strait data lie for the majority of the time in the <i>L</i><sub>Oz</sub> > <i>L</i><sub>T</sub> regime, but not universally. Also, comparison of direct and <i>L</i><sub>T</sub>-based estimates of <i>ε</i> exhibit reasonable similarity.</p>