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

D. A. Kazakov*, A. S. Samodurov

Marine Hydrophysical Institute of RAS, Sevastopol, Russia

* e-mail: engineer.dk@mail.ru

Abstract

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 α. 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.

Keywords

energy dissipation, stratified layers, turbulent exchange, buoyancy frequency, measuring complex, turbulence modelling, Prikerchensky area, internal wave collapse

Acknowledgments

The work was carried out under the state assignment on topic no. 0827-2019-0003 “Oceanological processes”.

For citation

Kazakov, D.A. and Samodurov, A.S., 2021. Estimation of the Vertical Turbulent Exchange Intensity in the Main Pycnocline Layer in the Prikerchensky Area of the Black Sea Shelf. Ecological Safety of Coastal and Shelf Zones of Sea, (2), pp. 94–105. doi:10.22449/2413-5577-2021-2-94–105 (in Russian).

DOI

10.22449/2413-5577-2021-2-94-105

References

  1. Wunsch, C. and Ferrari, R., 2004. Vertical Mixing, Energy, and the General Circulation of the Oceans. Annual Review of Fluid Mechanics, 36, pp. 281–314. https://doi.org/10.1146/annurev.fluid.36.050802.122121
  2. Samodurov, A.S., Dykman, V.Z., Barabash, V.A., Efremov, O.I., Zubov, A.G., Pavlenko, O.I. and Chukharev, A.M., 2005. “Sigma-1” Measuring Complex for the Investigation of Small-Scale Characteristics of Hydrophysical Fields in the Upper Layer of the Sea. Physical Oceanography, 15(5), pp. 311–322. doi:10.1007/s11110-006-0005-1
  3. Samodurov, A.S. and Ivanov, L.I., 2003. Mixing and Energy Dissipation Rate in Mediterranean Seas: an Intercomparison of Existing Models. In: A. Yilmaz, Ed., 2003. Proceeding of the “Second International Conference on Oceanography of the Eastern Mediterranean and Black Sea: Similarities and Differences of Two Interconnected Basins”. Ankara : Tübitak Publishers, 2003. P. 369–375.
  4. Samodurov, A.S., Lubitsky, A.A. and Panteleev, N.A., 1995. Contribution of Breaking Internal Waves to Structure Formation, Energy Dissipation, and Vertical Diffusion in the Ocean. Physical Oceanography, 6(3, pp. 177–190. https://doi.org/10.1007/BF02197516
  5. Gregg, M.C., 1977. Variations in the Intensity of Small-Scale Mixing in the Main Thermocline. Journal of Physical Oceanography, 7(3), pp. 436–454. https://doi.org/10.1175/1520-0485(1977)007<0436:VITIOS>2.0.CO;2
  6. McEwan, A.D., 1983. The Kinematics of Stratified Mixing Through Internal Wave-breaking. Journal of Fluid Mechanics, 128, pp. 47–57. doi:10.1017/S0022112083000373
  7. Osborn, T.R., 1980. Estimates of the Local Rate of Vertical Diffusion from Dissipation Measurements. Journal of Physical Oceanography, 10(1), pp. 83–89. https://doi.org/10.1175/1520-0485(1980)010<0083:EOTLRO>2.0.CO;2
  8. Gregg, M., 1989. Scaling Turbulent Dissipation in the Thermocline. Journal of Geophysical Research: Oceans, 94(C7), pp. 9686–9698. doi:10.1029/JC094iC07p09686
  9. Samodurov, A.S., 2016. Complimentarity of Different Approaches for Assessing Vertical Turbulent Exchange Intensity in Natural Stratified Basins. Physical Oceanography, (6), pp. 32–42. doi:10.22449/1573-160X-2016-6-32-42
  10. Zatsepin, A.G., Kremenetskiy, V.V., Stanichny, S.V. and Burdyugov, V.M., 2010. Black Sea Basin-Scale Circulation and Mesoscale Dynamics under Wind Forcing. In: A. V. Frolov and Yu. D. Resnyansky, 2010. Modern Problems of Ocean and Atmosphere Dynamics: The Pavel S. Lineykin memorial volume. Moscow: TRIADA LTD, pp. 347–368 (in Russian).
  11. Kubryakov, A.A., Belokopytov, V.N., Zatsepin, A.G., Stanichny, S.V. and Piotukh, V.B., 2019. The Black Sea Mixed Layer Depth Variability and Its Relation to the Basin Dynamics and Atmospheric Forcing. Physical Oceanography, 26(5), pp. 397–413. doi:10.22449/1573-160X-2019-5-397-413
  12. Munk, W., 1981. Internal Waves and Small-Scale Processes. In: B. A. Warren and C. Wunsch, Eds., 1981. Evolution of Physical Oceanography. MIT Press, pp. 264–291.

Full text

English version (PDF)

Russian version (PDF)