Articles | Volume 15, issue 2
https://doi.org/10.5194/os-15-459-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-15-459-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
29 Apr 2019
Research article |
| 29 Apr 2019
| 29 Apr 2019
Some aspects of the deep abyssal overflow between the middle and southern basins of the Caspian Sea
Javad Babagoli Matikolaei
Institute of Geophysics, University of Tehran, Tehran, Iran
Abbasali Aliakbari Bidokhti
CORRESPONDING AUTHOR
Institute of Geophysics, University of Tehran, Tehran, Iran
Maryam Shiea
Faculty of Marine Science and Technology, Science and Research Branch,
Islamic Azad University, Tehran, Iran
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Cited articles
Arakawa, A. and Suarez, M. J.: Vertical differencing of the primitive
equations in sigma coordinates, Mon. Weather Rev., 111, 34–45, 1983.
Ashida, K. and Shinzi, E.: Basic study on turbidity currents, Proceedings of
the Japan Society of Civil Engineers, Japan Society of Civil Engineers, 1975,
37–50, https://doi.org/10.2208/jscej1969.1975.237_37, 1975.
Astraldi, M., Gasparini, G. P., Gervasio, L., and Salusti, E.: Dense water
dynamics along the Strait of Sicily (Mediterranean Sea), J. Phys. Oceanogr.,
31, 3457–3475, 2001.
Aubrey, D. G: Conservation of biological diversity of the Caspian Sea and its
coastal zone, A proposal to the Global Environment Facility, Report to GEF,
1994.
Aubrey, D. G., Glushko T. A., and Ivanov, V. A.: North Caspian Basin:
Environmental status and oil and gas operational issues, Report for Mobil-oil
650 pp., 1994.
Baringer, M. O. and Price, J. F.: Mixing and spreading of the Mediterranean
outflow, Oceanographic Literature Review, 3, 436–437, 1998.
Bidokhti, A. A. and Ezam, M.: The structure of the Persian Gulf outflow
subjected to density variations, Ocean Sci., 5, 1–12,
https://doi.org/10.5194/os-5-1-2009, 2009.
Bondarenko, A. L: Currents of the Caspian Sea and formation of salinity of
the waters of the north part of the Caspian Sea, Nauka, Moscow, 6,
3019–3053, 1993.
Britter, R. E. and Linden, P. F.: The motion of the front of a gravity
current travelling down an incline, J. Fluid Mech., 99, 531–543, 1980.
Chen, J. L., Pekker, T., Wilson, C. R., Tapley, B. D., Kostianoy, A. G.,
Cretaux, J. F., and Safarov, E. S.: Long-term Caspian Sea level change,
Geophys. Res. Lett., 44, 6993–7001, 2017.
Cheng, R. T., Ling, C. H., Gartner, J. W., and Wang, P. F.: Estimates of
bottom roughness length and bottom shear stress in South San Francisco Bay,
California, J. Geophys. Res.-Oceans, 104, 7715–7728, 1999.
Dickson, R. R., Gmitrowicz, E. M., and Watson, A. J.: Deep-water renewal in
the northern North Atlantic, Nature, 344, 848–850, 1990.
Ellison, T. H. and Turner, J. S.: Turbulent entrainment in stratified flows,
J. Fluid Mech., 6, 423–448, 1959.
Escani, H. and Amini, A.: Impact of oil and gas industries on the Caspian Sea
ecosystem, The growth of Geography Education, 103, 26–31, 2013.
Ezam, M., Bidokhti, A. A., and Javid, A. H.: Numerical simulations of
spreading of the Persian Gulf outflow into the Oman Sea, Ocean Sci., 6,
887–900, https://doi.org/10.5194/os-6-887-2010, 2010.
Falcini, F. and Salusti, E.: Friction and mixing effects on potential
vorticity for bottom current crossing a marine strait: an application to the
Sicily Channel (central Mediterranean Sea), Ocean Sci., 11, 391–403,
https://doi.org/10.5194/os-11-391-2015, 2015.
Flierl, G. R.: Isolated eddy models in geophysics, Annu. Rev. Fluid Mech.,
19, 493–530, 1987.
Fogelqvist, E., Blindheim, J., Tanhua, T., Østerhus, S., Buch, E., and
Rey, F.: Greenland–Scotland overflow studied by hydro-chemical multivariate
analysis, Deep-Sea Res. Pt. I, 50, 73–102, 2003.
García, M. H.: Hydraulic jumps in sediment-driven bottom currents, J.
Hydraul. Eng., 119, 1094–1117, 1993.
Ghaffari, P. and Chegini, V.: Acoustic Doppler Current Profiler observations
in the southern Caspian Sea: shelf currents and flow field off Feridoonkenar
Bay, Iran, Ocean Sci., 6, 737–748, https://doi.org/10.5194/os-6-737-2010, 2010.
Ghaffari, P., Isachsen, P. E., and LaCasce, J. H.: Topographic effects on
current variability in the Caspian Sea, J. Geophys. Res.-Oceans, 118,
7107–7116, 2013.
Gill, A. E: Atmosphere-ocean dynamics, Elsevier, 662 pp., 1984.
Girton, J. B. and Sanford, T. B.: Descent and modification of the overflow
plume in the Denmark Strait, J. Phys. Oceanogr., 33, 1351–1364, 2003.
Griffiths, R. W: Gravity currents in rotating systems, Annu. Rev. Fluid
Mech., 18, 59–89, 1986.
Gunduz, M. and Özsoy, E.: Modelling seasonal circulation and thermohaline
structure of the Caspian Sea, Ocean Sci., 10, 459–471,
https://doi.org/10.5194/os-10-459-2014, 2014.
Huthnance, J. M: Circulation, exchange, and water masses at the ocean margin:
the role of physical processes at the shelf edge, Prog. Oceanogr., 35,
353–431, 1995.
Ibrayev, R. A., Özsoy, E., Schrum, C., and Sur, H. I.: Seasonal
variability of the Caspian Sea three-dimensional circulation, sea level and
air-sea interaction, Ocean Sci., 6, 311–329, https://doi.org/10.5194/os-6-311-2010,
2010.
Ismailova, B. B.: Geoinformation modeling of wind-induced surges on the
northern–eastern Caspian Sea, Math. Comput. Simulat., 67, 371–377, 2004.
Johnson, G. C. and Sanford, T. B.: Bottom and interfacial stresses on the
Mediterranean outflow, 10th Symposium on Turbulence and Diffusion, Portland,
Oregon, American Meteorological Society, 105–106, 1992.
Kara, A. B., Wallcraft, A. J., Metzger, E. J., and Gunduz, M.: Impacts of
freshwater on the seasonal variations of surface salinity and circulation in
the Caspian Sea, Cont. Shelf Res., 30, 1211–1225, 2010.
Karamzadeh, N.: Experimental investigation of water entrainment into a
density current, MSc Thesis, Shahid Chamran University, Ahvaz, Iran, 2004.
Kashefipour, S., Kooti, F., and Ghomeshi, M.: Effect of reservoir bed slope
and density current discharge on water entrainment, Environmental Hydraulics,
Proceedings of the 6th International Symposium on Environmental Hydraulics,
Athens, Greece, 23–25 June 2010, CRC Press, 2010.
Killworth, P. D.: Mixing of the Weddell Sea continental slope, Deep-Sea Res.,
24, 427–448, 1977.
Luyten, P. J., Jones, J. E., Proctor, R., Tabor, A., Tett, P., and
Wild-Allen, K.: COHERENS – A coupled hydrodynamical-ecological model for
regional and shelf seas: user documentation, MUMM Rep, Management Unit of the
Mathematical Models of the North Sea, 1999.
Mazaheri, S., Kamranzad, B., and Hajivalie, F.: Modification of 32 years
ECMWF wind field using QuikSCAT data for wave hindcasting in Iranian Seas, J.
Coast. Res., 65, 344–349, 2013.
Mityagina, M. I. and Lavrova, O. Y.: Multi-sensor satellite survey of surface
oil pollution in the Caspian Sea, Remote Sensing of the Ocean, Sea Ice,
Coastal Waters, and Large Water Regions, International Society for Optics and
Photonics, 9638, 2015.
Peeters, F., Kipfer, R., Achermann, D., Hofer, M., Aeschbach-Hertig, W.,
Beyerle, U., and Fröhlich, K.: Analysis of deep-water exchange in the
Caspian Sea based on environmental tracers, Deep-Sea Res. Pt. I, 47,
621–654, 2000.
Price, J. F. and Baringer, M. O.: Outflows and deep water production by
marginal seas, Prog. Oceanogr., 33, 161–200, 1994.
Shiea, M., Chegini, V., and Bidokhti, A. A.: Impact of wind and thermal
forcing on the seasonal variation of three-dimensional circulation in the
Caspian Sea, Indian J. Geo-Mar. Sci., 45, 671–686, 2016.
Smith, P. C.: A streamtube model for bottom boundary currents in the ocean,
Deep sea research and oceanographic abstracts, vol. 22, Elsevier, 1975.
Stern, M. E: Geostrophic fronts, bores, breaking and blocking waves, J. Fluid
Mech., 99, 687–703, 1980.
Terziev, F. S., Kosarev, A., and Kerimov, A. A.: The Seas of the USSR.
Hydrometeorology and Hydrochemistry of the Seas, Vol. IV: The Caspian Sea,
Issue 1: Hydrometorogical Conditions, Gidrometeoizdat, St. Petersburg,
Russia, 1992.
van Kessel, T. and Kranenburg, C.: Gravity current of fluid mud on sloping
bed, J. Hydraul. Eng., 122, 710–717, 1996.
Short summary
This study investigates the deep gravity current between the middle and southern Caspian Sea basins. Oceanographic data, a numerical model and dynamic models are used to consider the structure of this abyssal overflow. The deep overflow is driven by the density difference – mainly due to the temperature difference between the middle and southern basins – especially in winter. The
deep flow may be an important factor influencing oil pollution in the deeper region of the southern Caspian Sea.
This study investigates the deep gravity current between the middle and southern Caspian Sea...
