Distinguishing turbulent overturns in high-sampling-rate moored thermistor string observations
van Haren, H.; Gostiaux, L. (2015). Distinguishing turbulent overturns in high-sampling-rate moored thermistor string observations. J. Mar. Res. 73(1-2): 17-32. dx.doi.org/10.1357/002224015815782661
In: Journal of Marine Research. Sears Foundation for Marine Research, Yale University: New Haven, Conn.. ISSN 0022-2402; e-ISSN 1543-9542, more
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| Author keywords |
DETAILED OCEAN MIXING PARAMETER ESTIMATES; HIGH-RESOLUTION TEMPERATURE OBSERVATIONS; SALINITY-COMPENSATED INTRUSIONS; TURBULENT OVERTURN PATTERNS |
| Authors | | Top |
- van Haren, H., more
- Gostiaux, L.
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| Abstract |
Turbulent overturns are distinguished from salinity-compensated intrusions in high-resolution moored thermistor string observations. The buoyancy frequency N is used to make the time dimensionless, "t*." This results in a primary, visual means to easily compare the duration of overturns with N, the natural frequency that separates internal waves from turbulent overturns. As a secondary means, the shapes of overturns are investigated. Above various sloping topography between 500 and 1,000 m water depth where the buoyancy period varies between ~1,300 and 2,600 s, vertical overturns of ~40 m last ?t* =0.2–0.4. This corresponds with the timescale of growth of model-stratified turbulence in the wake of a grid. Smaller-scale, weaker-turbulent, shear-induced Kelvin-Helmholtz overturns of ~5 m are observed to last approximately ?t* = 0.03, whereas the passage of their train of multiple consecutive overturns lasts up to approximately ?t* = 0.95. Although the shape of overturns can distinguish salinity-compensated intrusions from turbulent overturns, the present observations from internal wave breaking above sloping topography show complex results of mixed features |
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