Use of a fiber-optic cable with a free-fall microstructure profiler

Gregg, Michael C.; Nodland, W.; Aagaard, E.; Hirt, Douglas E.

doi:10.1109/oceans.1982.1151839

Cited by 16 publications

(2 citation statements)

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“…The instruments that can directly measure small-scale fluctuations of vertical shear, conductivity, and temperature in profiling and towing modes were first developed in the United States (Osborn, 1978;Gregg et al, 1982;Dewey et aL, 1987), Canada Measurements, Processing, and Applications 295 (Oakey, 1982), Russia (Monin and Ozmidov, 1985;Aryan et al 1985), Germany (Prandke et aL, 1985) and Australia (Carter and Imberger, 1986). Since then different research groups have continued to improve and develop new microstructure instruments as in the cases of AMP and Chameleon (Moum et al, 1995), Baklan and Grif (Paka et aL, 1999), FLY (Simpson et al, 1996), and Epsonde (Oakey, 1988).…”

Section: Instrumentationmentioning

confidence: 99%

Mixing in shallow waters: Measurements, processing, and applications

Lozovatsky

Roget

Fernado

2005

J Ocean Univ. China

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Microstrueture profiling measurements taken on a shallow Black Sea shelf and in Lake Banyoles and Boadella reservoir (Both in Spain) are analyzed to investigate the influence of boundary-layer-induced turbulence of various sources on mixing in the water interior. The state of turbulence in shallow waters is examined and details of mierostructure data processing and error analysis are discussed. The dependence between averaged activity parameter AG and buoyancy Reynolds number Reb for the shelf turbulence indicates that for Reb < 1 the state of turbulence can be described by the fossil turbulence model, which postulates Ao --Re 3/2. For Re----b > 1, however, the influence of R-~eb on AG is weak, signifying that the buoyancy Reynolds number can no longer serve as the governing parameter for active turbulent mixing. The generation of turbulence by a one-minute long wind bursts (the Boadella reservoir) increases the averaged dissipation rate (e) of the surface mixed layer by more than 5 times (up to 3 × 10 -6 Wkg-l). The influence of the wind burlts was also traced below the thermocline, where turbulent patches with (¢) = (10 -7 -10 -6) Wkg -I were generated. It is shown that the geothermal convection in Lake Banyoles produces intermittent turbulent patches with characteristic dissipation rate (e) = (2 x 10-s _ 3 x 10-7) W kg -1, which influences the overall vertical mixing in the basin.

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Section: Instrumentationmentioning

confidence: 99%

Mixing in shallow waters: Measurements, processing, and applications

Lozovatsky

Roget

Fernado

2005

J Ocean Univ. China

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“…Stewart and Grant [29] were the first who successfully measured the turbulent fluctuations in a tidal channel based on the inertial and inertial-convective subranges. Several towed, moored, and profiling instruments thereafter developed to efficiently estimate important turbulent quantities such as dissipation rates of Turbulent Kinetic Energy (TKE), , temperature variance, and eddy diffusivity throughout the water column [8,14,18,25,28,32]. Despite extensive advances in measuring technology over the last 40 years, accurate and reliable estimates of turbulent quantities, e.g.…”

Section: Introductionmentioning

confidence: 99%

A wavelet-entropy based segmentation of turbulence measurements from a moored shear probe near the wavy sea surface

Paskyabi¹

2019

SN Appl. Sci.

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In this study, we explore the applicability of a wavelet-entropy based segmentation technique in reduction of motioninduced contaminations in time-domain from subsurface turbulence measurements made by a moving shear probe. After the quality screening of data, the Shannon entropy procedure is combined with a time-dependent adaptive wavelet thresholding method to split each 60-s long shear segment into a number of motion-reduced subblocks. The waveletentropy strategy leads to preventing the false detection effect caused by applying either wavelet de-noising or Shannon entropy alone for conditions where the turbulence (strongly) overlap with scales induced by waves or platform motions. The longest stationary subblock, with a size greater than 16-s, is then used to extract the Turbulent Kinetic Energy (TKE) dissipation rate,. Efficiency of the proposed method is verified by comparing with measurements made by a nearby free-falling microstructure profiler. While the quality of observations is constrained by a number of factors such as sensors' angle of attack, and the wave kinematical and dynamical effects, results demonstrate significant improvements, by approximately a factor of 5-10, compared with measurements from each 60-s segment using the Goodman et al. [13] method. Furthermore, the magnitudes of the motion-corrected using the proposed method is largely consistent with the scaling suggested by Terray et al. [30].

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