Hydrological Structure, Circulation and Water Mass Transport in the Gulf of Cadiz

Jose Miguel Rodrigues Alves, Xavier Carton, Isabel Ambar

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DOI: 10.4236/ijg.2011.24047                

Abstract

Hydrological and LADCP data from four experiments at sea (Semane 1999, 2000/1 2000/3, 2001) are used to describe the structure and circulation of Mediterranean Water in the Gulf of Cadiz. These data were gathered on meridional sections along 8?20′W and 6?15′W and between these longitudes on a zonal section along 35?50′N. The mesoscale and the submesoscale structures (Mediterranean Water Undercurrents, meddies, cyclones) observed along these sections are characterized in terms of thermohaline properties and of velocity. The transports of mass and salt in each class of density (North Atlantic Central Water, Mediterranean Water, North Atlantic Deep Water) are computed with an inverse model. The model indicates a general eastward flux in the Central Water layer, and a westward flux in the Mediterranean Water layer, but there is also a horizontal recirculation and entrainment in these two layers, as well as strong transports associated with the meddy and cyclone found during Semane 1999.

Keywords

Mediterranean Water, Gulf of Cadiz, Hydrology, Water Masses, Regional Scale Circulation, Inverse Model, Transport

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	F. Madelain, “Influence de la topographie de fond sur l’ecoulement mediterraneen entre le detroit de Gibraltar et le cap Saint Vincent,” Cahiers Oceanographiques, Vol. 22, 1970, pp.43-61.
[2]	C. Mauritzen, Y. Morel and J. Paillet, “Mediterranean Water Influence on the Central Waters of the North Atlantic Ocean,” Deep Sea Research Part I: Oceanographic Research Papers, Vol. 48, No. 2, 2001, pp. 347-381. doi:10.1016/S0967-0637(00)00043-1
[3]	I. Ambar and M. R. Howe, “Observations of the Mediterranean Outflow—II. The Deep Circulation in the Vicinity of the Gulf of Cadiz,” Deep Sea Research, Vol. 26, No. 5, 1979, pp. 555-568.
[4]	N. Daniault, J. P. Maze and M. Arhan, “Circulation and Mixing of the Mediterranean Water West of the Iberian Peninsula,” Deep Sea Research, Vol. 14, 1994, pp. 1685- 1714.
[5]	J. Ochoa and N. A. Bray, “Water Masses Exchange in the Gulf of Cadiz,” Deep Sea Research, Vol. 38, Suppl. 1, 1991, pp. S465-S503.
[6]	A. Peliz, P. Marchesiello, A. M. P. Santos, J. Dubert, A. Teles-Machado, M. Marta-Almeida and B. Le Cann, “Surface Circulation in the Gulf of Cadiz: 2. Inflow-Out- Flow Coupling and the Gulf of Cadiz Slope Current,” Journal of Geophysical Research, Vol. 114, No. 3, 2009, pp. 1-16. doi:10.1029/2008JC004771
[7]	X. Carton, L. Cherubin, J. Paillet, Y. Morel A. Serpette and B. Le Cann, “Meddy Coupling with a Deep Cyclone in the Gulf of Cadiz,” Journal of Marine Systems, Vol. 32, No. 1-3, 2002, pp. 13-42. doi:10.1016/S0924-7963(02)00028-3
[8]	A. S. Bower, L. Armi and I. Ambar, “Lagrangian Observations of Meddy Formation during A Mediterranean Undercurrent Seeding Experiment,” Journal of Physical Oceanography, Vol. 27, No. 12, 1997, pp. 2545-2575. doi:10.1175/1520-0485(1997)027<2545:LOOMFD>2.0.CO;2
[9]	I. Ambar, N. Serra, F. Neves and T. Ferreira, “Observations of the Mediterranean Undercurrent and Eddies in the Gulf of Cadiz during 2001,” Journal of Marine Systems, Vol. 71, No. 1-2, 2008, pp. 195-220. doi:10.1016/j.jmarsys.2007.07.003
[10]	H. L. Bryden, J. Candela and T. H. Kinder, “Exchange through the Straits of Gibraltar,” Progress in Oceanography, Vol. 33, No. 3, 1994, pp. 201-248. doi:10.1016/0079-6611(94)90028-0
[11]	A. Peliz, J. Dubert, P. Marchesiello and A. Teles- Machado, “Circulation in the Gulf of Cadiz: Model and Mean Flow Structure,” Journal of Geophysical Research, Vol. 112, 2007, C11015. doi:10.1029/2007JC004159
[12]	X. Carton, N. Daniault, J. Alves, L. Cherubin and I. Ambar, “Meddy Dynamics and Interaction with Neighboring Eddies Southwest of Portugal: Observations and Modeling,” Journal of Geophysical Research, Vol. 115, 2010, C06017. doi:10.1029/2009JC005646
[13]	L. Cherubin, X. Carton, J. Paillet, Y. Morel and A. Serpette, “Instability of the Mediterra-Nean Water Undercurrents Southwest of Portugal: Effects of Baroclinicity and of Topography,” Oceanologica Acta, Vol. 23, No. 5, 2000, pp. 551-573. doi:10.1016/S0399-1784(00)01105-1
[14]	N. Serra and I. Ambar, “Eddy Generation in the Mediterranean Undercurrent,” Deep Sea Research, Vol. 49, No. 19, 2002, pp. 4225-4243. doi:10.1016/S0967-0645(02)00152-2
[15]	N. Serra, I. Ambar and R. H. Kase, “Observations and Numerical Modeling of the Mediterranean Outflow Splitting and Eddy Generation,” Deep Sea Research Part II: Topical Studies in Oceanography, Vol. 52, No. 3-4, 2005, pp. 383-408. doi:10.1016/j.dsr2.2004.05.025
[16]	L. Lamas, A. Peliz, I. Ambar, A. Barbosa Aguiar, N. Maximenko and A. Teles-Machado: “Evidence of Time- mean Cyclonic Cell SW of Iberian Peninsula: The Mediterranean Outflow-Driven Beta-Plume,” Geophysical Re- search Letters, Vol. 37, 2010. L12606. doi:10.1029/2010GL043339