Experimental estimation of the coefficient of vertical turbulent exchange in a stratified layer of the black sea near the continental slope

2008 ◽  
Vol 18 (6) ◽  
pp. 308-318
Author(s):  
A. S. Samodurov ◽  
A. M. Chukharev
2019 ◽  
Vol 59 (2) ◽  
pp. 319-320
Author(s):  
N. N. Dmitrevskiy ◽  
R. A. Ananyev

In May and October 2017, expeditionary research was carried out in the area of Gelendzhik in the Black Sea at the R/V «Ashamba». The main tasks were the mapping of the seabed and the search for small-sized objects at the bottom of the water area using a WASSP WMB-3250 multibeam echo sounder. Surveys included areal surveying and drawing up bathymetric maps of test sites in Gelendzhik Bay and in the transition zone from the shelf to the continental slope. In addition, the echo sounder was used to search and determine the exact coordinates of the bottom seismograph installed at the seabed near the Divnomorskoye village in May 2016. The article presents the results of the work carried out.


2017 ◽  
Vol 53 (6) ◽  
pp. 632-640 ◽  
Author(s):  
A. N. Morozov ◽  
A. G. Zatsepin ◽  
S. B. Kuklev ◽  
A. G. Ostrovskii ◽  
S. V. Fedorov

Oceanology ◽  
2017 ◽  
Vol 57 (4) ◽  
pp. 492-504 ◽  
Author(s):  
O. I. Podymov ◽  
A. G. Zatsepin ◽  
A. G. Ostrovsky

2021 ◽  
Vol 28 (4) ◽  
Author(s):  
A. S. Samodurov ◽  
A. M. Chukharev ◽  
D. A. Kazakov ◽  
◽  
◽  
...  

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.


Author(s):  
D. A. Kazakov ◽  
A. S. Samodurov ◽  
◽  

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.


2001 ◽  
Vol 38 (2) ◽  
pp. 130-143
Author(s):  
A. I. Ginzburg ◽  
A. G. Kostyanoy ◽  
N. P. Nezlin ◽  
D. M. Solov'yev ◽  
R. R. Stanichnaya ◽  
...  

Author(s):  
Л. Есина ◽  
L. Esina ◽  
А. Хворощ ◽  
A. Hvorosch ◽  
Н. Есин ◽  
...  

Detailed studies of landslide formation on the continental slope of Near Caucasus part of Black Sea, we have made in the area between the Pshada– Olginka settlements allowed to explore the distribution of landslide formations on the continental slope and to establish their influence on the retreat of the shelf edge. The intensive destruction of shelf edge leads to a reduction in its width, the intense movement of sediments from the shelf and transporting them to the continental slope and deep-sea part in large quantities. The evolution and distribution of landslides are influenced by the geological structure of the navigation area, the width of the shelf, the rate of shoreline destruction and sediment transport from the shelf to the continental slope, underwater topography and slope declination, tectonic and seismic factors. Landslide processes on the coast and continental slope affect the modern coast changes, the bottom topography, the formation of Black Sea deep basins and the expansion of Black Sea. Coastal landslides pose a threat to coastal communities and national economic objects located in areas of high abrasion scarps of terraces, as well as for engineering structures on the continental shelf, continental slope and the seabed.


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