ESTIMATE OF DEPENDENCE OF THE VERTICAL TRBULENT DIFFUSION COEFFICIENT FROM BUOYANCY FREQUENCY FOR COASTAL ZONE OF THE BLACK SEA

2017 ◽  
Author(s):  
Lubov Globina ◽  
Lubov Globina
Keyword(s):  
Diffusion Coefficient ◽  
Active Layer ◽  
Black Sea ◽  
Eddy Diffusivity ◽  
The Black Sea ◽  
Small Scale ◽  
Buoyancy Frequency ◽  
Shelf Area ◽  
Turbulent Diffusion Coefficient ◽  
Horizontal Convection

The article highlights the most important studies of oceanographic processes, such as horizontal convection, winter cascading on the shelf and continental slope, the processes in the bottom of the Black Sea. The results of the study of small-scale structure of the shelf upper active layer of the Black Sea in 2014 are discussed. The new information about the distribution of the eddy diffusivity with depth in the coastal part of the Heracleian peninsula is given. The investigated dependence vertical turbulent diffusion coefficient from buoyancy frequency at the active layer is found to be has a quadratic character for the entire shelf area and doesn’t depend on the stratification.

ESTIMATE OF DEPENDENCE OF THE VERTICAL TRBULENT DIFFUSION COEFFICIENT FROM BUOYANCY FREQUENCY FOR COASTAL ZONE OF THE BLACK SEA

2017 ◽  
Author(s):  
Lubov Globina ◽  
Lubov Globina
Keyword(s):  
Diffusion Coefficient ◽  
Active Layer ◽  
Black Sea ◽  
Eddy Diffusivity ◽  
The Black Sea ◽  
Small Scale ◽  
Buoyancy Frequency ◽  
Shelf Area ◽  
Turbulent Diffusion Coefficient ◽  
Horizontal Convection

The article highlights the most important studies of oceanographic processes, such as horizontal convection, winter cascading on the shelf and continental slope, the processes in the bottom of the Black Sea. The results of the study of small-scale structure of the shelf upper active layer of the Black Sea in 2014 are discussed. The new information about the distribution of the eddy diffusivity with depth in the coastal part of the Heracleian peninsula is given. The investigated dependence vertical turbulent diffusion coefficient from buoyancy frequency at the active layer is found to be has a quadratic character for the entire shelf area and doesn’t depend on the stratification.

scholarly journals Estimation of the Vertical Turbulent Exchange Intensity in the Main Pycnocline Layer in the Prikerchensky Area of the Black Sea Shelf

2021 ◽  
Author(s):  
D. A. Kazakov ◽  
A. S. Samodurov ◽  
◽  
Keyword(s):  
Black Sea ◽  
Measurement Data ◽  
Water Area ◽  
Turbulent Exchange ◽  
The Black Sea ◽  
Buoyancy Frequency ◽  
Turbulent Diffusion Coefficient ◽  
Shelf Slope ◽  
Sigma 1 ◽  
Deep Water Area

The paper investigates the seasonal variability of the vertical turbulent exchange coefficient in the upper stratified layer of the Black Sea. The expedition data used in this work containing information on the microstructure of physical fields were obtained in different hydrological seasons covering the northeastern part of the Black Sea in the Prikerchensky area of the shelf slope. The data were collected during cruises of r/v “Professor Vodyanitsky” in 2016–2019 using “Sigma-1” sounding complex. Based on the semi-empirical methods of assessment of vertical turbulent exchange in the deep-water area of the Black Sea, the dependence of the vertical turbulent diffusion coefficient K on the buoyancy frequency N in the studied layer was established from the flow fluctuation characteristics, with the corresponding graphs and their approximating power-law dependences K  A  N  plotting. In addition, the vertical distribution of the K coefficient with depth was analyzed. Comparative analysis of the obtained dependences with the results of the 1.5D model was carried out. The analysis of the measurement data showed that the results obtained in this work do not contradict the original model. The results can also be used to assess the vertical fluxes of heat, salt and other dissolved chemical and biological substances depending on stratification in the studied part of the Black Sea for different seasons.

Intensive Internal Waves with Anomalous Heights in the Black Sea Shelf Area

2019 ◽  
Vol 55 (1) ◽  
pp. 99-109 ◽  
Author(s):  
V. G. Bondur ◽  
A. N. Serebryany ◽  
V. V. Zamshin ◽  
L. L. Tarasov ◽  
E. E. Khimchenko
Keyword(s):  
Internal Waves ◽  
Black Sea ◽  
The Black Sea ◽  
Shelf Area

Field studies of variation scales of gravitational capillary waves and near-water wind in the Black Sea shelf area

2010 ◽  
Vol 46 (2) ◽  
pp. 232-238 ◽  
Author(s):  
V. V. Bakhanov ◽  
N. A. Bogatov ◽  
A. S. Volkov ◽  
A. V. Ermoshkin ◽  
E. M. Zuykova ◽  
...  
Keyword(s):  
Black Sea ◽  
Field Studies ◽  
Capillary Waves ◽  
The Black Sea ◽  
Shelf Area

scholarly journals Basic Regularities of Vertical Turbulent Exchange in the Mixed and Stratified Layers of the Black Sea

2021 ◽  
Vol 28 (4) ◽  
Author(s):  
A. S. Samodurov ◽  
A. M. Chukharev ◽  
D. A. Kazakov ◽  
◽  
◽  
...  
Keyword(s):  
Experimental Data ◽  
Black Sea ◽  
Dissipation Rate ◽  
Turbulent Exchange ◽  
The Black Sea ◽  
Buoyancy Frequency ◽  
Exchange Coefficient ◽  
Semi Empirical ◽  
Turbulence Generation ◽  
Turbulent Exchange Coefficient

Purpose. The purpose of the study is to assess the coefficient of vertical turbulent exchange for different layers of the Black Sea basin based on the experimental data on microstructure of the physical fields obtained for the period 2004–2019 in the Black Sea and using the semi-empirical models. Methods and Results. For the upper mixed layer, the turbulent energy dissipation rate ɛ and the exchange coefficient were calculated using the velocity fluctuation spectra based on the Kolmogorov hypotheses on the turbulence spectrum inertial range. In the stratified layers, the turbulence coefficient and the dissipation rate were experimentally determined both from the spectra of the velocity horizontal fluctuations’ gradients and the vertical spectra of temperature fluctuations using the concept of the effective scale of turbulent patches. Depending on the features of the hydrological regime and the prevailing energy contributors to turbulence generation, five layers were identified and described (including their characteristic power dependences of the vertical turbulent diffusion coefficients K on the buoyancy frequency N) using the 1.5D-model of vertical turbulent exchange for the basin under study. For the stratified layers, the 1.5D-model results were comparatively analyzed with those of the other semi-empirical and theoretical models describing the most probable hydrophysical processes in each specific layer; the relations for the vertical turbulent exchange coefficient were obtained depending on the buoyancy frequency. Conclusions. Comparison of the experimental data collected under different hydrometeorological conditions with the simulations resulted from the known turbulence models for the sea upper layer showed that the best agreement between the simulation and measurement data was provided by a multiscale model taking into account three basic mechanisms of turbulence generation: current velocity shear, instability of wave motions, and wave breaking. The turbulent exchange coefficient dependencies on depth are conditioned by the effect of the turbulence dominant source at a given level. In the stratified layers, the exchange coefficient dependence on buoyancy frequency is determined by the hydrophysical processes in each layer; the relations obtained for individual layers indicate intensity of the contributions of vertical advection, internal wave breakings, turbulence diffusion and geothermal flux.

scholarly journals A Thermohaline Inverse Method for Estimating Diathermohaline Circulation and Mixing

2014 ◽  
Vol 44 (10) ◽  
pp. 2681-2697 ◽  
Author(s):  
Sjoerd Groeskamp ◽  
Jan D. Zika ◽  
Bernadette M. Sloyan ◽  
Trevor J. McDougall ◽  
Peter C. McIntosh
Keyword(s):  
Diffusion Coefficient ◽  
Inverse Method ◽  
Climate Model ◽  
Salinity Gradient ◽  
Surface Flux ◽  
Volume Transport ◽  
Heat Fluxes ◽  
Small Scale ◽  
Mixing Processes ◽  
Turbulent Diffusion Coefficient

Abstract The thermohaline inverse method (THIM) is presented that provides estimates of the diathermohaline streamfunction , the downgradient along-isopycnal diffusion coefficient K, and the isotropic downgradient turbulent diffusion coefficient D of small-scale mixing processes. This is accomplished by using the water mass transformation framework in two tracer dimensions: here in Absolute Salinity SA and Conservative Temperature Θ coordinates. The authors show that a diathermal volume transport down a Conservative Temperature gradient is related to surface heating and cooling and mixing, and a diahaline volume transport down an Absolute Salinity gradient is related to surface freshwater fluxes and mixing. Both the diahaline and diathermal flows can be calculated using readily observed parameters that are used to produce climatologies, surface flux products, and mixing parameterizations for K and D. Conservation statements for volume, salt, and heat in (SA, Θ) coordinates, using the diahaline and diathermal volume transport expressed as surface freshwater and heat fluxes and mixing, allow for the formulation of a system of equations that is solved by an inverse method that can estimate the unknown diathermohaline streamfunction and the diffusion coefficients K and D. The inverse solution provides an accurate estimate of , K, and D when tested against a numerical climate model for which all these parameters are known.

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