Ocean Science
www.ocean-sci.net
1812-0784
1812-0792
3
1
2007
10.5194/os-3-1-2007
http://www.ocean-sci.net/3/1/2007/
http://www.ocean-sci.net/3/1/2007/os-3-1-2007.html
http://www.ocean-sci.net/3/1/2007/os-3-1-2007.pdf
1
16
2007-01-24
A nested circulation model for the North Aegean Sea
V. Kourafalou
K. Tsiaras
Hellenic Center for Marine Research, Anavyssos, Greece
Rosenstiel School of Marine and Atmospheric Science, Univ. of Miami, Miami, Fl, USA
A multi-nested approach has been employed for numerical simulations in the
northern part of the Aegean Sea in the framework of the MFSTEP
(Mediterranean Forecast System: Toward Environmental Predictions) project.
The high resolution (~1.6 km) hydrodynamic model of the North Aegean
Sea (NAS) has been nested within a coarser model of the Eastern
Mediterranean (resolution ~3.6 km) which is also nested within a basin
scale model for the Mediterranean Sea (resolution of ~7 km). The high
resolution of the NAS model allows the representation of topographic details
that have never been reproduced in modelling studies of the region. Such
details can enhance the simulation of coastal features, but can also
influence basin-scale processes, such as the pathways of waters of Black Sea
origin inflowing at the Dardanelles Straits and bifurcating through island
passages.
<br><br>
We employ comparisons of the North Aegean and Eastern Mediterranean models
in terms of computed flow fields and distribution of hydrodynamic
properties, to evaluate the nesting procedure, the initialization
requirements and the ability of a nested model to perform reliable short
term simulations that employ high resolution atmospheric forcing, when
initialized from a coarser OGCM.
<br><br>
We show that the topographic details of the high resolution, nested NAS
model affect the distribution of the Dardanelles plume and the evolution of
coastal currents, while the imposed high frequency, high resolution
atmospheric forcing allows for the formation of an overall energetic flow
field after a few days of spin-up period. Increased resolution and smaller
coastal depth in the NAS simulations influence the flow through island
passages and straits. A longer initialization procedure results in the
establishment of stronger currents and better-developed buoyant plumes.
Atlas, R.: Atmospheric observations and experiments to assess their usefulness in data assimilation, Journal of the Meteorological Society of Japan, 75(1B), 111–130, 1997.
Balopoulos, E. T., Collins, M. B., and James, A. E.: Residual circulation in a coastal embayment of the Eastern Mediterranean Sea (Thermaikos Bay, N.W. Aegean), Thalassographica, 9, 7–22, 1986.
Bignami, F., Marullo, S., Santoleri, R., and Schiano, M. E.: Longwave radiation budget in the Mediterranean Sea, J. Geophys. Res., 100(C2), 2501–2514, 1995.
Blumberg, A. F. and Mellor, G. L.: Diagnostic and prognostic numerical circulation studies of the South Atlantic Bight, J. Geophys. Res., 88(C8), 4579–4592, 1983.
Castellari, S., Pinardi, N., and Leaman, K.: A model study of air-sea interactions in the Mediterranean Sea, J. Mar. Syst., 18, 89–114, 1998.
Demirov, E. and Pinardi, N.: Simulation of the Mediterranean Sea circulation from 1979 to 1993. Part I: The interannual variability, J. Mar. Syst., 33/34, 23–50, 2002.
Flather, R. A.: A tidal model of the northwest European continental shelf, Memoires Societe Royale des Sciences de Liege, Series 6(10), 141–164, 1976.
Gill., A. E. : Atmosphere-Ocean Dynamics, Academic Press, New York, 662 pp., 1982.
Hellermann, S. and Rosenstein, M.: Normal wind stress over the world ocean with error estimates, J. Phys. Oceanogr., 13, 1093–1104, 1983.
Karageorgis, A. P., Kaberi, H. G., Tengberg, A., Zervakis, V., Hall, P. O. J., and Anagnostou, Ch. L.: Comparison of particulate matter distribution, in relation to hydrography, in the mesotrophic Skagerrak and the oligotrophic northeastern Aegean Sea, Continental Shelf Research, 23, 1787–1809, 2003.
Kondo, J.: Air-sea bulk transfer coefficients in diabatic conditions, Boundary-Layer Meteorol., 9, 91–112, 1975.
Kontoyiannis, H., Kourafalou, V. H., and Papadopoulos, V.: The seasonal characteristics of the hydrology and circulation in the Northwest Aegean Sea (Eastern Mediterranean): observations and modeling, J. Geophys. Res., 108(C9), 3302, doi:10.1029/2001JC001132, 2003.
Korres, G. and Lascaratos, A.: A one-way nested eddy resolving model of the Aegean and Levantine basins: implementation and climatological runs, Ann. Geophys., 21, 205–220, 2003.
Kourafalou, V. H., Oey, L.-Y., Wang, J. D., and Lee, T. N.: The fate of river discharge on the continental shelf. Part I: modelling the river plume and the inner-shelf coastal current, J. Geophys. Res., 101(C2), 3415–3434, 1996.
Kourafalou, V. H. and Barbopoulos, K.: High resolution simulations on the North Aegean Sea seasonal circulation, Ann. Geophys., 21, 251–265, 2003.
Kourafalou, V. H., Savvidis, Y. G., Koutitas, C. G., and Krestenitis, Y. N.: Modeling studies on the processes that influence matter transfer on the Gulf of Thermaikos (NW Aegean Sea), Continental Shelf Research, 24, 203–222, 2004.
Lowe, P. R.: An approximating polynomial for the computation of saturation vapor pressure, J. Appl. Meteorol., 16, 100–103, 1977.
Mellor, G. L. and Yamada, T.: Development of a turbulence closure model for geophysical fluid problems, Rev. Geophys. Space Phys., 20(4), 851–875, 1982.
Bungiorno Nardelli, B., Larnicol, G., D'Acunzo, E., Santoleri, R., Marullo, S., and Le Traon, P.Y.: Near Real Time SLA and SST products during 2-years of MFS pilot project: processing, analysis of the variability and of the coupled patterns, Ann. Geophys., 21, 103–121, 2003.
Natale, S., Sorgente, R., Gabersek, S., Ribotti, A., and Olita, A.: Central Mediterranean Sea forecast: effects of high-resolution atmospheric forcings, Ocean Sci. Discuss., 3, 637–669, 2006.
Nittis, K., Zervakis, V., Papageorgiou, E., and Perivoliotis, L.: Atmospheric and Oceanic observations from the POSEIDON buoy network: Initial results. The Global Atmosphere and Ocean System, special issue – POSEIDON: An Integrated Operational Oceanographic System, Vol. 8, 2–3, pp 87–99, 2002.
Nittis, K., Perivoliotis, L., Korres, G., Tziavos, C., and Thanos, I.: Operational monitoring and forecasting for marine environmental applications in the Aegean Sea, Environmental Modelling and Software, 21, 243–257, 2006.
Olson, D. B., Kourafalou, V. H., Johns, W. H., Samuels, G., and Veneziani, M.: Aegean Surface Circulation from a Satellite-tracked Drifter Array, J. Phys. Oceanogr., in press, 2007.
Pinardi, N., Allen, I., Demirov, E., De Mey, P., Korres, G., Lascaratos, A., Le Traon, P.-Y., Maillard, C., Manzella G., and Tziavos, C.: The Mediterranean Ocean Forecasting System: First phase of implementation (1998–2001), Ann. Geophys., 21, 3–20, 2003.
Poulos, S. E., Drakopoulos, P. G., and Collins, M. B.: Seasonal variability in sea surface oceanographic conditions in the Aegean Sea (Eastern Mediterranean): an overview, J. Mar. Syst., 13, 225–244, 1997.
Rosati, A. and Miyakoda, K.: A general circulation model for upper ocean circulation, J. Phys. Oceanogr., 18, 1601–1626, 1988.
Smagorinsky, J.: General circulation experiments with the primitive equations, I. The basic experiment, Mon. Wea. Rev., 91, 99–164, 1963.
Sofianos, S. S., Skliris, N., Mantziafou, A., Lascaratos, A., Zodiatis, G., Lardner, R., Hayes, D., and Georgiou, G.: Nesting operational forecasting models in the Eastern Mediterranean: active and slave mode, Ocean Sci. Discuss., 3, 1225–1254, 2006.
Therianos, A. D.: Rainfall and geographical distribution of river runoff in Greece, Bull. Geol. Soc. Greece, XI, 28–58 (in Greek), 1974.
Thorpe, S. E., Heywood, K. J., Stevens, D. P., and Brandon, M. A.: Tracking passive drifters in a high resolution ocean model: implications for interannual variability of larval krill transport to South Georgia, Deep-Sea Res. I, 51, 909–920, 2004.
Zervakis, V., Georgopoulos, D., and Drakopoulos, P. G.: The role of the North Aegean in triggering the recent Eastern Meiterranean climate changes, J. Geophys. Res., 105, 26 103–26 116, 2000.
Zervakis, V. and Georgopoulos, D.: Hydrology and Circulation in the North Aegean (eastern Mediterranean) throughout 1997–1998, Mediterranean Marine Science, 3, 1, 7–21, 2002.
Zodiatis, G. and Balopoulos, E.: Structure and characteristics of fronts in the North Aegean Sea, Boll. Oceanol. Theor. Appl., XI, 113–124, 1993.
Zodiatis, G.: Advection of the Black Sea water in the north Aegean Sea, Global Atmos. Ocean Syst., 2, 41–60, 1994.
Zodiatis, G., Alexandri, S., Pavlakis, P., Jönnson, L., Kallos, G., Demetropoulos, A., Georgiou, G., Theodorou, A., and Balopoulos, E.: Tentative study of flow patterns in the North Aegean Sea using NOAA-AVHRR images and 2D model simulations, Ann. Geophys., 14, 1221–1231, 1996.
Zavatarelli, M., Pinardi, N., Kourafalou, V. H., and Maggiore, A.: Diagnostic and prognostic model studies of the Adriatic Sea circulation: Seasonal variability, J. Geophys. Res., 107(C1), doi:10.1029/2000JC000210, 2002.