Hydrophysics

Hydrophysics

The Impacts of the Atmospheric Forcing on Thermocline Layer Structure in the Caspian Sea

Document Type : Original Article

Author
Maryam Shiea
Caspian Climate Company, Mashhad
Abstract
In this study, the structure of thermocline layer in the Middle Caspian Sea (MCS) and Southern Caspian Sea (SCS) for 2004 was investigated using the three-dimensional ocean model COHERENS. The simulation results for three transects (along South-North, in Southern Caspian Sea "along 38.91N", in Middle Caspian Sea "along 42.45N" show that, in winter, season thermocline is almost eliminated and the temperature is uniform up to a depth of 100 m. After the erosion of surface thermocline in winter, this layer is recreated in spring. The results show the formation of a strong thermocline in summer and in the beginning of autumn, the thickness of the thermocline is reduced. In general, seasonal variability of water temperature is confined to the upper 120m layers. Also transects of Southern and Middle Caspian Sea show some special regions in which thermocline layer structure is stronger. Thus thermocline layer is created at a depth less than 25m from the sea surface water in eastern coast of SCS and at a depth less than 20m from the sea surface water in western coast of MCS during the summer.
Keywords
Caspian Sea
thermocline
COHERENS model
Temperature
seasonal variation

Subjects

[1] Aubrey DG, Glushko TA, Ivanov VA, et al, editors. North Caspian Basin: Environmental status and oil and gas operational issues. Mobil Oil; 1994.
[2] Aubrey DG. Conservation of biological diversity of the Caspian Sea and its coastal zone. A proposal to the Global Environment Facility. Report to GEF. 1994.
[3] Lebedev SA, Kostianoy AG. Satellite altimetry of the Caspian Sea. Sea, Moscow. 2005;366.
[4] Peeters F, Kipfer R, Achermann D, Hofer M, Aeschbach-Hertig W, Beyerle U, Imboden DM, Rozanski K, Fröhlich K. Analysis of deep-water exchange in the Caspian Sea based on environmental tracers. Deep Sea Research Part I: Oceanographic Research Papers. 2000 Apr 30;47(4):621-54.
 [5] Tuzhilkin VS, Kosarev AN, Thermohaline Structure and General Circulation of the Caspian Sea Waters. In:  Kostianov AG, Kosarev AN, editor. The Caspian Sea Environment (Handbook of Environmental Chemistry); 2005. P.33-58.
[6] Luyten PJ, Jones JE, Proctor R, Tabor A, Tett P, Wild-Allen K. COHERENS–A coupled hydrodynamical-ecological model for regional and shelf seas: user documentation. MUMM Report, Management Unit of the Mathematical Models of the North Sea. 1999;914.
[7] Steinhorn I. Salt flux and evaporation. Journal of physical oceanography. 1991;21(11):1681-3.
[8] Kara AB, Wallcraft AJ, Metzger EJ, Gunduz M. Impacts of freshwater on the seasonal variations of surface salinity and circulation in the Caspian Sea. Continental Shelf Research. 2010 Jun 15;30(10):1211-25.
[9] Turuncoglu UU, Giuliani G, Elguindi N, Giorgi F. Modelling the Caspian Sea and its catchment area using a coupled regional atmosphere-ocean model (RegCM4-ROMS): model design and preliminary results. Geoscientific Model Development. 2013; 6(2): 283–99.
[10] شیعه مریم، علی‌اکبری‌بیدختی عباسعلی، چگینی وحید. تعیین اثر واداشت­های مهم بر گردش دریای خزر با استفاده از شبیه­سازی عددی. مجله ژئوفیزیک ایران. 1394؛9(3):118-142.
[11] شیعه مریم، علی‌اکبری بیدختی عباسعلی. مطالعه و بررسی پدیده فراجوشی در سواحل شرقی خزر میانی با استفاده از شبیه سازی عددی. مجله فیزیک زمین و فضا. 1394؛41(3):535-545.

  • Receive Date 16 April 2016
  • Revise Date 15 October 2016
  • Accept Date 15 November 2016