Nudging Time-Scale Sensitivity of a Simplified Black Sea CIL Forcing with a Three-Dimensional Idealized Bosphorus Hydrodynamic Model
Abstract
Hydrodynamics of the Bosphorus Strait is examined under idealized
conditions with a three-dimensional numerical model. In particular, penetration
of a simplified Cold Intermediate Layer (CIL) of the Black Sea into the Strait
specifıed at the boundary is simulated with the aim of testing the sensitivity
of the idealized model with respect to nudging strength. Successful penetration of a CIL-like
stratification can only be achieved by inflowing nudging time-scales less than
or equal to one day, while the outflowing nudging strength is found to be
insignificant. However, numerical instabilities at the boundary are observed
for strong nudging cases with tnudg ≤ 0.01 day suggesting
that a careful selection of the nudging time-scale is important to achieve
successful simulations of the CIL even in this highly idealized setup of the
Bosphorus strait. The presence of CIL altering the temperature distribution
within the northern section of the idealized channel has a significant impact
on the exchange through the strait. CIL reduces the density difference across
the strait resulting in decreased layer fluxes and velocities, while a
two-layer sense hydraulic control still holds at the sill.
Keywords
Kaynakça
- Altıok, H., Sur, H.İ. & Yüce, H. (2012). Variation of the cold intermediate water in the Black Sea exit of the Strait of İstanbul (Bosphorus) and its transfer through the strait. Oceanologia, 54(2), 233.Altıok, Η. & Kayışoğlu, M. (2015). Seasonal and interannual variability of water exchange in the Strait of Istanbul. Mediterranean Marine Science, 16(3), 644-655.Andersen, J.J.E.C. & Carmack, E.C. (1984). Observations of Chemical and Physical Fine-structure in a Strong Pycnoline, Sea of Marmara. Deep-Sea Res., 2, 877-886.Armi, L. (1986). The hydraulics of two flowing layers with different densities. Journal of Fluid Mechanics, 163(1), 27-58.Armi, L. & Farmer, D.M. (1986). Maximal two-layer exchange through a contraction with barotropic netflow. Journal of Fluid Mechanics, 164, 27-51.Aydoğdu, A., Pinardi, N., Özsoy, E., Danabasoglu, G., Gürses, Ö. & Karspeck, A. (2018). Circulation of the Turkish Straits System under interannual atmospheric forcing. Ocean Science 14, 999-1019.Beşiktepe, Ş., Özsoy, E., Latif M.A. & Oğuz T. (2000). Marmara Denizi'nin hidrografisi ve Dolaşımı, (Hydrography and Circulation of the Marmara Sea). Marmara Sea 2000 Symposium, İstanbul, Nov. 11-12, 2000, 14 pp. (in Turkish).Beşiktepe, Ş., Özsoy, E. & Ünlüata, Ü. (1993). Filling of the Marmara Sea by the Dardanelles lower layer inflow. Deep Sea Research Part I: Oceanographic Research Papers, 40(9), 1815-1838.Beşiktepe, Ş.T., Sur, H.İ., Özsoy, E., Latif, M.A., Oǧuz, T. & Ünlüata, Ü. (1994). The circulation and hydrography of the Marmara Sea. Progress in Oceanography, 34(4), 285-334.Dalziel, S.B. (1991). Two-layer hydraulics: a functional approach. Journal of Fluid Mechanics, 223(1), 135-163.Defant, A. (1961). Physical Oceanography. Pergamon Press, London, 1961. Vol. 1, pp. xvi + 729; Vol. 2, pp. Viii + 598.Durski, S.M., Glenn, S.M. & Haidvogel, D.B. (2004). Vertical mixing schemes in the coastal ocean: Comparison of the level 2.5 Mellor‐Yamada scheme with an enhanced version of the K profile parameterization. Journal of Geophysical Research: Oceans, 109(C1).Farmer, D.M. & Armi, L. (1986). Maximal two-layer exchange over a sill and through the combination of a sill and contraction with barotropic flow. Journal of Fluid Mechanics, 164, 53-76.Garrett, C. & Gerdes, F. (2003). Hydraulic control of homogeneous shear flows. Journal of Fluid Mechanics, 475, 163-172.Gregg, M.C. & Özsoy, E. (1999). Mixing on the Black Sea shelf north of the Bosphorus. Geophysical Research Letters, 26(13), 1869-1872Gregg, M.C. & Özsoy, E. (2002). Flow, water mass changes, and hydraulics in the Bosphorus. Journal of Geophysical Research: Oceans, 107(C3).Gregg, M.C., Özsoy, E. & Latif, M.A. (1999). Quasi-steady exchange flow in the Bosphorus, Geophysical Research Letters, 26, 83–86.Haidvogel, D.B., Arango, H.G., Hedström, K., Beckmann, A., Malanotte-Rizzoli, P. & Shchepetkin, A.F. (2000). Model evaluation experiments in the North Atlantic Basin: simulations in nonlinear terrain-following coordinates. Dynamics of Atmospheres and Oceans, 32(3), 239-281.Hedström, K.S. (2009). DRAFT Technical Manual for a Coupled Sea-Ice. Ocean Circulation Model (Version 3), US Department of the Interior, Mineral Management Service, Anchorage, Alaska, Arctic Region Supercomputing Center, University of Alaska Fairbanks, Contract M07PC13368.Helfrich, K.R. (1995). Time-dependent two-layer hydraulic exchange flows. Journal of Physical Oceanography, 25(3), 359-373.Hogg, A.M., Ivey, G.N. & Winters, K.B. (2001). Hydraulics and mixing in controlled exchange flows. Journal of Geophysical Research: Oceans (1978-2012), 106(C1), 959-972.Jarosz, E., Teague, W.J., Book, J.W. & Beşiktepe, Ş. (2011a). Observed volume fluxes in the Bosphorus Strait. Geophysical Research Letters, 38(21).Jarosz, E., Teague, W.J., Book, J.W. & Beşiktepe, Ş. (2011b). On flow variability in the Bosphorus Strait. J. Geophys. Res., 116, C08038, doi:10.1029/2010JC006861.Jordà, G., Von Schuckmann, K., Josey, S.A., Caniaux, G., García-Lafuente, J., Sammartino, S., Özsoy, E., Polcher, J., Notarstefano, G., Poulain, P-M., Adloff, F., Salat, J., Naranjo, C., Schroeder, K., Chiggiato, J., Sannino, G. & Macías, D. (2016). The Mediterranean Sea heat and mass budgets: Estimates, uncertainties and perspectives. Progress in Oceanography, 156, 174-208.Lane-Serff, G.F., Smeed, D.A. & Postlethwaite, C.R. (2000). Multi-layer hydraulic exchange flows. Journal of Fluid Mechanics, 416, 269-296.Large, W.G., McWilliams, J.C. & Doney, S.C. (1994). Oceanic vertical mixing: A review and a model with a nonlocal boundary layer parameterization. Reviews of Geophysics, 32(4), 363-403.Latif, M.A., Özsoy, E., Oğuz, T. & Ünlüata, Ü. (1991). Observations of the Mediterranean inflow into the Black Sea. Deep Sea Research Part A. Oceanographic Research Papers, 38, 711-723.Marchesiello, P., McWilliams, J.C. & Shchepetkin, A. (2001). Open boundary conditions for long-term integration of regional oceanic models. Ocean modelling, 3(1-2), 1-20.Mellor, G.L. & Yamada, T. (1982). Development of a turbulence closure model for geophysical fluid problems. Reviews of Geophysics, 20(4), 851-875.Oğuz, T. (2005). Hydraulic adjustments of the Bosphorus exchange flow. Geophysical research letters, 32(6).Oğuz, T., Özsoy, E., Latif, M.A., Sur, H.İ. & Ünlüata, Ü. (1990). Modeling of hydraulically controlled exchange flow in the Bosphorus Strait. Journal of Physical Oceanography, 20(7), 945-965.Orlanski, I. (1976). A simple boundary condition for unbounded hyperbolic flows. Journal of computational physics, 21(3), 251-269.Ovchinnikov, I.M. & Popov, Yu.I. (1991). Evolution of the Cold Intermediate Layer in the Black Sea. Oceanology, 27, 555-560.Özsoy, E., Latif, M.A., Sur, H.İ, & Goryachkin, Y. (1996). A review of the exchange flow regime and mixing in the Bosphorus strait. Bulletin-Institut Oceanographique Monaco-Numero Special, 187-204.Özsoy, E. & Ünlülata, Ü. (1997). Oceanography of the Black Sea: a review of some recent results. Earth-Science Reviews, 42(4), 231-272.Özsoy, E., & Ünlüata, Ü. (1998). The Black Sea, in: A. R. Robinson and K. Brink (editors), The Sea: The Global Coastal Ocean: Regional Studies and Synteses, 11, John Wiley and Sons, New York, pp. 889-914. Özsoy, E. (1999). Sensitivity to Global Change in Temperate Euro-Asian Seas (the Mediterranean, Black Sea and Caspian Sea): A Review, in P. Malanotte-Rizzoli and V. N. Eremeev, (editors), The Eastern Mediterranean as a Laboratory Basin for the Assessment of Contrasting Ecosystems, NATO Science Series 2, Environmental Security, 51, Kluwer Academic Publishers, Dordrecht, pp. 281-300.Özsoy, E., Di Iorio, D., Gregg, M.C. & Backhaus, J.O. (2001). Mixing in the Bosphorus Strait and the Black Sea continental shelf: observations and a model of the dense water outflow. Journal of marine systems, 31(1), 99-135.Özsoy, E., Latif, M.A., Beşiktepe, S., Çetin, N., Gregg, M.C., Belokopytov Goryachkin, Y. & Diaconu, V. (1998). The Bosphorus Strait: Exchange Fluxes, Currents and Sea-Level Changes. NATO Science Series 2 Environmental Security, 47(2), 1-28.Özsoy, E., Latif, M.A., Tuğrul, S. & Ünlülata, Ü. (1995). Exchanges with the Mediterranean, fuxes, and boundary mixing processes in the Black Sea. Bulletin de l'Institut ocèanographique, Monaco, Special Number 15, CIESM Science Series No. 1, Monaco 1-25.Özsoy, E., Oğuz, T., Latif, M.A, Ünlüata, Ü., Sur, H.İ. & Beşiktepe, Ş. (1988). Oceanography of the Turkish Straits - Second Annual Report, Volume I. Physical Oceanography of the Turkish Straits, Institute of Marine Sciences, METU, Erdemli, İçel.Özsoy, E., Oğuz, T., Latif, M.A. & Ünlüata, Ü. (1986). Oceanography of the Turkish Straits - First Annual Report, Volume I, Physical Oceanography of the Turkish Straits, Institute of Marine Sciences, METU, Erdemli, İçel, Turkey, 223pp.Öztürk, M., Ayat, B., Aydoğan, B., & Yüksel, Y. (2012). 3D Numerical modeling of stratified flows: case study of the Bosphorus Strait. Journal of Waterway, Port, Coastal, and Ocean Engineering, 138(5), 406-419.Pinardi, N. (2009). Misurare il mare: Luigi Ferdinando Marsili nell'Egeo e nel Bosforo, Bononia University Press, 1679-1680.Pratt, L.J. (1986). Hydraulic control of sill flow with bottom friction. Journal of Physical Oceanography, 16(11), 1970-1980.Pratt, L.J. (2008). Critical conditions and composite Froude numbers for layered flow with transverse variations in velocity. Journal of Fluid Mechanics, 605, 281-291.Raymond, W.H. & Kuo, H.L. (1984). A radiation boundary condition for multi‐dimensional flows. Quarterly Journal of the Royal Meteorological Society, 110(464), 535-551.Sannino, G., Sözer, A. & Özsoy, E. (2017). A high-resolution modelling study of the Turkish Straits System. Ocean Dynamics, 67(3-4), 397-432.Smagorinsky, J. (1963). General circulation experiments with the primitive equations: I. the basic experiment. Monthly weather review, 91(3), 99-164.Schroeder, K., Garcìa-Lafuente, J., Josey, S. A., Artale, V., Nardelli, B.B., Carrillo, A., Gačić, M, Gasparini, G.P., Herrmann, M., Lionello, P., Ludwig, W., Millot, C., Özsoy, E., Pisacane, G., Sánchez-Garrido, J.C., Sannino, G., Santoleri, R., Somot, S., Struglia, M., Stanev, E., Taupier-Letage, I., Tsimplis, M.N., Vargas-Yáñez, M., Zervakis, V., Zodiatis, G. (2012). Chapter 3: Circulation of the Mediterranean Seaand its Variability, In:Lionello,P.(ed.),The Climate of theMediterranean Region - From the past to the future, Elsevier, 592 pSmeed, D.A. (2000). Hydraulic control of three-layer exchange flows: application to the Bab al Mandab. Journal of Physial Oceanography, 30(10), 2574-2588.Soffientino, B. & Pilson. M.E.Q. (2005). The Bosphorus Strait. A Special Place in the History of Oceanography. Oceanography, 18(2), 16-23.Song, Y. & Haidvogel, D. (1994). A semi-implicit ocean circulation model using a generalized topography-following coordinate system. Journal of Computational Physics, 115(1), 228-244.Sözer, A. (2013). Numerical modeling of the bosphorus exchange flow dynamics (Doctoral dissertation, Ph. D. thesis, Institute of Marine Sciences, Middle East Technical University, Erdemli, Mersin, Turkey).Sözer, A. & Özsoy, E. (2002). A three-dimensional model of Bosphorus Strait dynamics. In The 2nd Meeting on the Physical Oceanography of Sea Straits, Villefranche, 15th-19th April (pp. 207-210).Sözer, A. & Özsoy, E. (2017). Modeling of the Bosphorus exchange flow dynamics. Ocean dynamics, 67(3-4), 321-343.Stanev, E.V., Grashorn, S. & Zhang, Y.J. (2017). Cascading ocean basins: numerical simulations of the circulation and interbasin exchange in the Azov-Black-Marmara-Mediterranean Seas system. Ocean Dynamics, 67(8), 1003-1025.Tolmazin, D. (1985). Changing coastal oceanography of the Black Sea II: Mediterranean effluent. Progress in oceanography, 15(4): 277-316.Tuğrul, S., Beşiktepe, T. & Salihoğlu, I. (2002). Nutrient exchange fluxes between the Aegean and Black Seas through the Marmara Sea. Mediterranean Marine Science, 3(1), 33-42.Umlauf, L. & Burchard, H. (2003). A generic length-scale equation for geophysical turbulence models. Journal of Marine Research, 61(2), 235-265.Ünlüata, Ü., Oğuz, T., Latif, M.A. & Özsoy, E. (1990). On the physical oceanography of the Turkish Straits. In The physical oceanography of sea straits (pp. 25-60). Springer Netherlands.Warner, J.C., Sherwood, C.R., Arango, H.G. & Signell, R.P. (2005). Performance of four turbulence closure models implemented using a generic length scale method. Ocean Modeling, 8(1), 81-113Wilkin, J.L., Arango, H.G., Haidvogel, D.B., Lichtenwalner, C., Glenn, S.M. & Hedström, K.S. (2005). A regional ocean modeling system for the Long‐term Ecosystem Observatory. Journal of Geophysical Research: Oceans, 110(C6).Winters, K.B. & Seim, H.E. (2000). The role of dissipation and mixing in exchange flow through a contracting channel. Journal of Fluid Mechanics, 407, 265-290.