Energy Characteristics of the Marmara Sea Water Circulation in 2008

S. G. Demyshev, S. V. Dovgaya✉, M. V. Shokurov

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

✉ e-mail: dovgayasvetlana0309@yandex.ru

Abstract

Purpose . The main objectives of the study consisted in analyzing the Marmara Sea energy and in identifying the basic reasons for formation of its circulation features in 2008.

Methods and Results . The numerical experiment on modeling the Marmara Sea circulation and evaluating its energy characteristics on the example of 2008 was carried out based on the eddy-resolving nonlinear hydrodynamic model of Marine Hydrophysical Institute, RAS. The horizontal resolution of the model was 1.22 × 0.83 km, 18 horizons were used over vertical and the time step was 0.5 min. Temperature, salinity and water discharge through the Bosporus and the Dardanelles were preset according to the available measurement data. The applied fields of atmospheric forcing were obtained from the calculation by the regional atmospheric model MM5. The volume-integrated and year-averaged contributions of the terms in the equations of the kinetic and potential energy budgets were analyzed. The basic factors of change in the Marmara Sea kinetic energy consisted in the buoyancy force action, wind, and vertical and horizontal mixing. Having been analyzed, the volume-average summands in the equation of rate of the kinetic energy change have shown that the wind-induced energy influx was compensated mainly by vertical friction, and the buoyancy force action – by horizontal friction. On the average, in course of a year the potential energy changed mainly due to its horizontal transport conditioned by the effect of the currents located in front of the straits, vertical diffusion and the buoyancy force impact. The results of analysis of the energy transitions permitted to reveal that in the upper sea layer, the mesoscale vortices were formed directly under the wind influence and as a result of the currents’ baroclinic instability. Generation of the sub-mesoscale vortices in the coastal regions was affected predominantly by the processes of baroclinic instability. In the region near the Bosporus, increase of the horizontal gradients in the density field and, consequently, intensification of dynamic processes are the results of inflow of the Black Sea waters with lower density.

Conclusions . Study of the energy characteristics of the Marmara Sea water circulation permitted to conclude that baroclinic instability and wind are two of the basic sources of eddy formation in this basin.

Keywords

numerical hydrodynamic model, Marmara Sea, kinetic energy, potential energy, cyclone, anticyclone, baroclinic instability

Acknowledgements

The investigation is carried out within the framework of the state task on theme No. 0827-2018-0003 "Fundamental studies of oceanological processes determining state and evolution of marine environment under the influence of natural and anthropogenic factors based on observation and modeling methods".

Original russian text

Original Russian Text © S. G. Demyshev, S. V. Dovgaya, M. V. Shokurov, 2019, published in MORSKOY GIDROFIZICHESKIY ZHURNAL, Vol. 35, Iss. 4, pp. 307–321 (2019)

For citation

Demyshev, S.G., Dovgaya, S.V. and Shokurov, M.V., 2019. Energy Characteristics of the Marmara Sea Water Circulation in 2008. Physical Oceanography , 26(4), pp. 275-287. doi:10.22449/1573-160X-2019-4-275-287

DOI

10.22449/1573-160X-2019-4-275-287

References

  1. Beşiktepe, T.Ş., Sur, H.I., Özsoy, E., Latif, M.A., Oguz, T. and Ünlüata, Ü., 1994. The Circulation and Hydrography of the Marmara Sea. Progress in Oceanography, [e-journal] 34(4), pp. 285-334. https://doi.org/10.1016/0079-6611(94)90018-3
  2. Demyshev, S.G., Dovgaya, S.V. and Ivanov, V.A., 2012. Numerical Modeling of the Influence of Exchange through the Bosporus and Dardanelles Straits on the Hydrophysical Fields of the Marmara Sea. Izvestiya, Atmospheric and Oceanic Physics, [e-journal] 48(4), pp. 418-426. doi: 10.1134/S0001433812040056
  3. Demyshev, S.G., Dovgaya, S.V. and Shokurov, M.V., 2016. Effect of Heat Flow, Precipitation and Evaporatio on the Dynamics of the Marmara Sea Surface Water. Physical Oceanography, [e-journal] (3), pp. 3-13. doi:10.22449/1573-160X-2016-3-3-13
  4. Chiggiato, J., Jarosz, E., Book, J.W., Dykes, J., Torrisi, L., Poulain, P-M., Gerin, R., Horstmann, J. and Beşiktepe, Ş., 2012. Dynamics of the Circulation in the Sea of Marmara: Numerical Modeling Experiments and Observations from the Turkish Straits System Experiment. Ocean Dynamic, [e-journal] 62(1), pp. 139-159. doi:10.1007/s10236-011-0485-5
  5. Aydogdu, A., Pinardi, N., Özsoy, E., Danabasoglu, G., Gürses, Ö. and Karspeck, A., 2018. Circulation of the Turkish Straits System under Interannual Atmospheric Forcing. Ocean Science, [e-journal] 14(5), pp. 999-1019. https://doi.org/10.5194/os-2018-7
  6. Zalesny, V.B., Gusev, A.V. and Fomin, V.V., 2016. Numerical Model of Nonhydrostatic Ocean Dynamics Based on Methods of Artificial Compressibility and Multicomponent Splitting. Oceanology, [e-journal] 56(6), pp. 876-887. https://doi.org/10.1134/S0001437016050167
  7. Demyshev, S.G., 2004. Energy of the Black Sea Climatic Circulation. Part I: Discrete Equations of the Time Rate of Change of Kinetic and Potential Energy. Russian Meteorology and Hydrology, (9), pp. 65-81.
  8. Demyshev, S.G. and Dymova, O.A., 2016. Analyzing Intraannual Variations in the Energy Characteristics of Circulation in the Black Sea. Izvestiya, Atmospheric and Oceanic Physics, [e-journal] 52(4), pp. 386-393. https://doi.org/10.1134/S0001433816040046
  9. Oguz, T., Özsoy, E., Latif, M.A., Sur, H.I. and Ünlüata, Ü., 1990. Modeling of Hydraulically Controlled Exchange Flow in the Bosphorus Strait. Journal of Physical Oceanography, [e-journal] 20(7), pp. 945-965. doi:10.1175/1520-0485(1990)020<0945:MOHCEF>2.0.CO;2
  10. Zapevalov, А.S., 2005. Seasonal Variability of Vertical Distributions of Temperature and Salinity in the Sea of Marmara. Russian Meteorology and Hydrology, (2), pp. 78-84.
  11. Beşiktepe, T.Ş., 2003. Density Currents in the Two-layer Flow: an Example of Dardanelles Outflow. Oceanologica Acta, [e-journal] 26(3), pp. 243-253. https://doi.org/10.1016/S0399-1784(03)00015-X
  12. Beşiktepe, T.Ş., Özsoy, E. and Ünlüata, Ü., 1993. Filling of the Marmara Sea by the Dardanelles Lower Layer Inflow. Deep Sea Research Part I: Oceanographic Research Papers, [e-journal] 40(9), pp. 1815-1838. https://doi.org/10.1016/0967-0637(93)90034-Z
  13. Pacanowski, R.C. and Philander, S.G.H., 1981. Parameterization of Vertical Mixing in Numerical Models of Tropical Oceans. Journal of Physical Oceanography, [e-journal] 11(11), pp. 1443-1451. doi:10.1175/1520-0485(1981)011<1443:POVMIN>2.0.CO;2
  14. Kamenkovich, V.M., Koshlyakov, M.N. and Monin, A.S., 1987. [Synoptic Eddies in the Ocean]. Leningrad: Gidrometeoizdat, 509 p. (in Russian).
  15. Thomas, L.N., Tandon, A. and Mahadevan, A., 2008. Submesoscale Processes and Dynamics. In: eds. M. W. Hecht, H. Hasumi, 2008. Ocean Modeling in an Eddying Regime. Washington D.C.: American Geophysical Union, pp. 17-38. doi:10.1029/177GM04

Download the article (PDF)