Study of the Process of the Black Sea Upper Layer Mixing in the Zone of the Rim Current Activity in Winter Based on the Drifters Data

A. A. Sizov✉, T. M. Bayankina, A. V. Yurovsky

Marine Hydrophysical Institute, Russian Academy of Sciences, Sevastopol, Russian Federation

✉ e-mail: sizov_anatoliy@mail.ru

Abstract

Purpose. The process of the upper layer mixing in the western Black Sea during the heightened heat flux from its surface in the winter season is studied. The mechanism forming average temperature both in the upper mixed layer and in the layer below the lower boundary in the seasonal thermocline is analyzed.

Methods and Results. Measurements of the thermistor chain drifters as well as the MERRA reanalysis data and the simulation results of the regional model RegCM4 which included the ERA-Interim reanalysis (2012–2014) data as the input information, were involved in the calculations. It is revealed that growth of the wind speed and the total heat flux from the sea surface was accompanied by increase of the current velocity that resulted in intensification of turbulent mixing in the upper layer (40–50 m depth) and lowering of its average temperature. It is also found out that increase of the current velocity was followed by deepening of the seasonal thermocline and cold intermediate layer; whereas its decrease contributed to elevation of cold waters from the lower boundary of the upper mixed layer to the smaller depths. At the same time, diminution of the cold intermediate layer depth was observed. At lowering of the current velocity, this resulted in decrease of the upper mixed layer average temperature, and growth of the temperature in the layer below the seasonal thermocline.

Conclusions. The current velocity intensification induces deepening of the seasonal thermocline and the cold intermediate layer; whereas its decrease promotes elevation of these layers to smaller depths. This process results in lowering of the upper mixed layer average temperature.

Keywords

Rim Current, upper mixed layer, cold intermediate layer, seasonal thermocline, atmospheric forcing

Acknowledgements

The investigation is carried out within the framework of the state task on theme No. 0827-2018-0001 “Fundamental studies of interaction processes in the ocean-atmosphere system conditioning regional spatial-temporal variability of natural environment and climate”. The authors are grateful to Dr. Sci. (Phys.-Math.), Professor V.V. Efimov for discussing the data and the obtained results as well as to the reviewer for his helpful remarks.

Original russian text

Original Russian Text © A. A. Sizov, T. M. Bayankina, A. V. Yurovsky, 2019, published in MORSKOY GIDROFIZICHESKIY ZHURNAL, Vol. 35, Iss. 3, pp. 287–298 (2019)

For citation

Sizov, A.A., Bayankina, T.M. and Yurovsky, A.V., 2019. Study of the Process of the Black Sea Upper Layer Mixing in the Zone of the Rim Current Activity in Winter Based on the Drifters Data. Physical Oceanography, 26(3), pp. 260-270. doi:10.22449/1573-160X-2019-3-260-270

DOI

10.22449/1573-160X-2019-3-260-270

References

  1. Krivosheya, V.G., Ovchinnikov, I.M. and Skirta, A.Yu., 2002. [Interannual Variability of the Cold Intermediate Layer Renewal in the Black Sea]. In: A. G. Zatsepin, M. V. Flint, eds., 2002. Multidisciplinary Investigations of the Northeast Part of the Black Sea. Мoscow: Nauka, pp. 27-39 (in Russian).
  2. Titov, V.B., 2003. Effect of Multiannual Variability of Climatic Conditions on the Hydrological Structure and Interannual Renewal of the Cold Intermediate Layer in the Black Sea. Oceanology, 43(2), pp. 164-172.
  3. Belokopytov, V.N., 2010. Interannual Variations of the Renewal of Waters of the Cold Intermediate Layer in the Black Sea for the Last Decades. Physical Oceanography, [e-journal] 20(5), pp. 347-355. https://doi.org/10.1007/s11110-011-9090-x
  4. Belokopytov, V.N., 2014. [Climatic Variability of the Black Sea Density Structure]. Ukrainian Hydrometeorological Journal, (14), pp. 227-235. Available at:http://uhmj.odeku.edu.ua/klimaticheskaya-izmenchivost-plotnostnoj-struktury- chernogo-morya/ [Accessed: 15 December 2018] (in Russian).
  5. Ivanov, V.A. and Belokopytov, V.N., 2011. Oceanography of the Black Sea. Sevastopol: MHI, 210 p.
  6. Bayankina, T.M., Sizov, A.A. and Jurovskij, A.V., 2017. [On the Role of Cold Invasion in the Formation of the Black Sea Winter Surface Temperature Anomaly]. Processes in GeoMedia, (3), pp. 565-572 (in Russian).
  7. Kubryakov, A.A. and Stanichny, S.V., 2015. Mesoscale Eddies in the Black Sea from Satellite Altimetry Data. Oceanology, [e-journal] 55(1), pp. 56-67. https://doi.org/10.1134/S0001437015010105
  8. Ginzburg, A.I., Zatsepin, A.G., Kostianoy, A.G. and Sheremet, N.A., 2006. Mesoscale Water Dynamics. In: A. G. Kostianoy and A. N. Kosarev, eds., 2006. The Black Sea Environment. The Handbook of Environmental Chemistry, vol. 5Q. Berlin : Springer, pp. 195-215. https://doi.org/10.1007/698_5_062
  9. Kubryakov, A.A. and Stanichny, S.V., 2015. Seasonal and Interannual Variability of the Black Sea Eddies and Its Dependence on Characteristics of the Large-Scale Circulation. Deep-Sea Research Part I: Oceanographic Research Papers, [e-journal] 97, pp. 80-91. http://dx.doi.org/10.1016/j.dsr.2014.12.002
  10. Tolstosheev, A.P., Lunev, E.G. and Motyzhev, S.V., 2014. Analiz Rezul'tatov Naturnykh Eksperimentov s Termoprofiliruyushchimi Dreyfuyushchimi Buyami v Chernom More I Drugikh Rayonakh Mirovogo Okeana [Analysis of In-Situ Experiments with Temperature- Profiling Drifters in the Black Sea and Other Areas of the Word Ocean]. Morskoy Gidrofizicheskiy Zhurnal, (5), pp. 9-32 (in Russian).
  11. Kubryakov, A.A. and Stanichny, S.V., 2012. Reconstruction of Mean Dynamic Topography of the Black Sea for Altimetry Measurements. Isvestiya, Atmospheric and Ocean Physics, [e-journal] 48(9), pp. 973-979. https://doi.org/10.1134/S0001433812090095
  12. Kubryakov, A.A. and Stanichny, S.V., 2013. Estimating the Quality of the Retrieval of the Surface Geostrophic Circulation of the Black Sea by Satellite Altimetry Data Based on Validation with Drifting Buoy Measurements. Isvestiya, Atmospheric and Ocean Physics, [e-journal] 49(9), pp. 930-938. doi:10.1134/S0001433813090089
  13. Kubryakov, A.A., Stanichny, S.V., Zatsepin, A.G. and Kremenetskiy, V.V., 2016. Long- Term Variations of the Black Sea Dynamics and Their Impact on the Marine Ecosystem. Journal of Marine Systems, [e-journal] 163, pp. 80-94. https://doi.org/10.1016/j.jmarsys.2016.06.006
  14. Anisimov, A.E., Yarovaya, D.A. and Barabanov, V.S., 2015. Reanalysis of Atmospheric Circulation for the Black Sea-Caspian Region. Physical Oceanography, [e-journal] (4), pp. 13-25. doi:10.22449/1573-160X-2015-4-13-25
  15. Podymov, O.I., Zatsepin, A.G. and Ostrovsky, A.G., 2017. Vertical Turbulent Exchange in the Black Sea Pycnocline and Its Relation to Water Dynamics. Oceanology, [e-journal] 57(4), pp. 492-504. https://doi.org/10.1134/S0001437017040142
  16. Efimov, V.V. and Yurovsky, A.V., 2017. Formation of Vorticity of the Wind Speed Field in the Atmosphere over the Black Sea. Physical Oceanography, [e-journal] (6), pp. 3-11. doi:10.22449/1573-160X-2017-6-3-11
  17. Efimov, V.V. and Mikhaylova, N.V., 2017. The Mesoscale Atmospheric Vortex as a Manifestation of the Novorossiysk Bora. Isvestiya, Atmospheric and Ocean Physics, [e-journal] 53(4), pp. 449- 458. https://doi.org/10.1134/S000143381704003X
  18. Kubryakov, A.A., Stanichny, S.V. and Volkov, D.L., 2017. Quantifying the Impact of Basin Dynamics on the Regional Sea Level Rise in the Black Sea. Ocean Science, [e-journal] 13(3), pp. 443-452. https://doi.org/10.5194/os-13-443-2017

Download the article (PDF)