AYBE- Katı Yer Bilimleri Lisansüstü Programı - Yüksek Lisans
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ÖgeComparison Between Hydrostatic And Nonhydrostatic Simulations Of Turkish Strait System(Eurasia Institute of Earth Sciences, 2018-12-13) Parkan, Ece Nil ; Ilıcak, Mehmet ; 602161002 ; Solid Earth Sciences ; Katı Yer Bilimleri Anabilim DalıTurkish Strait System (TSS) consists of Dardanelle Strait, Marmara Sea and Bosporus Strait is a coupled system where the fully coupled effects are significantly different than three individual members of the system. Due to the deep inflow from Mediterranean Sea and also outflow of the Black Sea, Marmara Sea acts like a buffer zone of these two important water masses. In addition, the Marmara Sea has its own separate temperature and salinity water characteristics that is resulted in significantly different stratified layers than the neighbor seas. The more saline (38 psu) and warmer (26⁰C) waters from the Mediterranean Sea mixes with colder (22⁰C) and less saline (18 psu) Black Sea water in the Marmara Sea and creates cold intermediate layer (CIL) which is highly effected from surface fluxes that will change its thickness and depth from the surface. We employ a 3D hydrostatic and non-hydrostatic ocean general circulation model in this study. The hydrostatic simulation is carried out from Sanino et al, 2017, where they investigate the impact of volume fluxes on the TSS circulation. The initial conditions for the three different Seas are based on the measurements that are taken from the CTD's during the summer season. This initiliazed warm upper surface waters along basins, couldn't reach to climatological cold surface water of Black Sea without heat fluxes like in the other months of the year. Surface waters, summer time is the special case, are colder in general. (According to the SHOD(2009), Month of February Dardanelle Strait has temperature down to 8.6⁰C; and in the Bosprous Strait it is 4.5⁰C) On the other hand, boundary condition of the Aegean side of the domain, a problem seems to exist due to mesoscale eddies created and trapped because of the closed boundary conditions. However, we believe that this will not affect the Marmara basin because of short integration time length. Our aim to understand the performance of non-hydrostatic terms in mixing of exchange flows in TSS. In our control simulation, we find that there are four different layers in the temperature field in the Dardanelle Strait whereas in the Bosporus Strait, there are 3 layers seen as a result of density differences of two water distinct sources (Black Sea and Eagean Sea). In the salinity field of the Bosporus Strait, vertical mixing effect is observed close to the surface waters in which salinity concentration is decreased. The interfacial layer between surface and deep layers is also increasing in thickness towards the Bosporus Strait. Circulation in the Marmara Sea is effected dominantly from jet flux issued to the Sea of Marmara from Bosporus. Jet has three branches which splits into firstly to the west side of the Bosporus Strait, opening of the Izmit Bay, secondly to southern boundary of the Marmara Sea by bending and converging with the big gyre in the middle and lastly to the North. This Northern branch also splits into two; one which directly flows trough the northern side of the Marmara Island and combined with small scale eddy by increasing its circulation speed and the other branch is shooting into the Marmara islands. This extended part of the jet also splits into many branches and flows into the entrance to the Dardanelle Strait. In our non-hydrostatic simulation, we find that the differences between two simulations are minor in the deep at this resolution. Surprisingly, the largest differences are close to the surface in terms of circulation and mesoscale eddy processes. The main reason behind this difference is resolving the evolution of vorticity using the full 3D vertical acceleration term in the non-hydrostatic simulation.