Scientia Marina, Vol 75, No 1 (2011)

Analysis of a 44-year hindcast for the Mediterranean Sea: comparison with altimetry and in situ observations

Enrique Vidal-Vijande
Instituto Mediterráneo de Estudios Avanzados (CSIC-UIB) , Spain

Ananda Pascual
Instituto Mediterráneo de Estudios Avanzados (CSIC-UIB) , Spain

Bernard Barnier
LEGI , France

Jean-Marc Molines
LEGI , France

Joaquín Tintoré
Instituto Mediterráneo de Estudios Avanzados (CSIC-UIB) , Spain


We study the interannual and seasonal variability in the Mediterranean Sea over the period 1958-2004 by comparing a numerical simulation (the 1/4º ORCA-R025 G70 model run, ‘ORCA’ hereafter) with altimetry and the MEDAR temperature and salinity database. The model is forced by the ERA40 atmospheric forcing and has a salinity restoring term applied at surface. Comparing temperature between ORCA and MEDAR shows good interannual variability agreement (correlations of ~0.8 in the western Mediterranean and ~0.5 in the eastern Mediterranean) at surface layers (0-150 m), but slightly higher mean values in the model (0.08-0.16°C). The salinity analysis shows that the surface salinity restoring term has obliterated most of the interannual variability. Mean surface salinities are slightly lower in the model (~0.3), replicated in deeper layers to a lesser degree, and could mean that the restoring term applies insufficient evaporation to compensate for a weak atmospheric forcing (ERA40) water loss flux. The sea level analysis comparing sea surface height (SSH) and steric height from ORCA and sea level anomalies from altimetry (1993-2004) shows good correlations (~0.8) in the interannual variability and annual cycle. However, the model’s SSH overestimates (~15 mm/yr) observed positive altimetric trends (~3-4 mm/yr). In an attempt to identify the source of this overestimation, a water budget calculation was performed between the horizontal and vertical water fluxes in the Mediterranean Sea. Horizontal transport through the main straits shows appropriate values when compared to observations. Thus, the cause of the exaggerated SSH trend is probably a water flux imbalance. By improving surface salinity restoring and atmospheric forcing, the ORCA simulations can provide very promising tools for studies of interannual variability in the Mediterranean Sea.


sea level; altimetry; temperature; salinity; modelling; Mediterranean Sea

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Alvarez, A., J. Tintoré, G. Holloway, M. Eby and J.M. Beckers. – 1994. Effect of topographic stress on circulation in the western mediterranean. J. Geophys. Res., 99(C8): 16,053-16,064.

Astraldi, M., S. Balopoulos, J. Candela, J. Font, M. Gacic, G.P. Gasparini, B. Manca, A. Theocharis and J. Tintoré. – 1999. The role of straits and channels in understanding the characteristics of mediterranean circulation. Prog. Oceanogr., 44(1-3): 65-108. doi:10.1016/S0079-6611(99)00021-X

Barnier, B., L. Brodeau, J. le Sommer, J.M. Molines, T. Penduff, S. Theetten, A.-M. Treguier, G. Madec, A. Biastoch, C. Böning, J. Dengg, S. Gulev, B.R. Badie, J. Chanut, G. Garric, S. Alderson, A. Coward, B. de Cuevas, A. New, K. Haines, G. Smith, S. Drijfhout, W. Hazeleger, C. Severijns and P. Myers. – 2007. Eddy-permitting ocean circulation hindcasts of past decades. In: P. Killworth, A. Pirani and H. Cattle (eds.), CLIVAR Exchanges, No. 42(Vol. 12 No.3).

Barnier, B., G. Madec, T. Penduff, J.-M. Molines, A.-M. Treguier, J.L. Sommer, A. Beckmann, A. Biastoch, C. Böning, J. Dengg, C. Derval, E. Durand, S. Gulev, E. Remy, C. Talandier, S. Theetten, M. Maltrud, J. McClean and B.D. Cuevas. – 2006. Impact of partial steps and momentum advection schemes in a global ocean circulation model at eddy-permitting resolution. Ocean Dynamics, 56: 543-567. doi:10.1007/s10236-006-0082-1

Beckers, J.M., M. Rixen, P. Brasseur, J.M. Brankart, A. Elmoussaoui, M. Crépon, Herbaut, F. Martel, F.V. den Berghe, L. Mortie, A. Lascaratos, P. Drakopoulos, G. Korres, K. Nittis, N. Pinardi, E. Masetti, S. Castellari, P. Carini, J. Tintoré, A. Alvarez, S. Monserrat, D. Parrilla, R. Vautard and S. Speich. – 2002. Model intercomparison in the Mediterranean: Medmex simulations of the seasonal cycle. J. Mar. Syst., 33-34: 215-251. doi:10.1016/S0924-7963(02)00060-X

Bethoux, J., B. Gentili and D. Tailliez. – 1998. Warming and freshwater budget change in the Mediterranean since the 1940s, their possible relation to the greenhouse effect. Geophys. Res. Lett., 25: 1023-1026. doi:10.1029/98GL00724

Bethoux, J.P. and B. Gentili. – 1996. The Mediterranean Sea, coastal and deep-sea signatures of climatic and environmental changes. J. Mar. Syst., 7(2-4): 383-394. doi:10.1016/0924-7963(95)00008-9

Bethoux, J.P. and B. Gentili. – 1999. Functioning of the Mediterranean Sea: past and present changes related to freshwater input and climate changes. J. Mar. Syst., 20(1-4): 33-47. doi:10.1016/S0924-7963(98)00069-4

Bouzinac, C., J. Font and J. Johannessen. – 2003. Annual cycles of sea level and sea surface temperature in the western Mediterranean Sea. J. Geophys. Res., 108(C8): 19,477-19,498.

Candela, J. – 2001. Mediterranean Water and Global Circulation. In: Ocean Circulation and Climate, pp. 419-429. Academic Press.

Demirov, E. and N. Pinardi. – 2002. Simulation of the Mediterranean Sea circulation from 1979 to 1993: Part I. the interannual variability. J. Mar. Syst., 33-34: 23-50. doi:10.1016/S0924-7963(02)00051-9

Ducet, N., P.-Y. Le Traon and G. Reverdin. – 2000. Global high-resolution mapping of ocean circulation from Topex/Poseidon and ERS-1 and -2. J. Geophys. Res. C, 105(C8): 19,477-19,498.

Fernández, V., D.E. Dietrich, R.L. Haney and J. Tintoré. – 2005. Mesoscale, seasonal and interannual variability in the Mediterranean Sea using a numerical ocean model. Prog. Oceanogr., 66: 321-340. doi:10.1016/j.pocean.2004.07.010

García Lafuente, J., J. Delgado and F. Criado. – 2002. Inflow interruption by meteorological forcing in the strait of Gibraltar. Geophys. Res. Lett., 29(19): 1914. doi:10.1029/2002GL015446

Gomis, D., M.N. Tsimplis, B. Martín-Míguez, A.W. Ratsimandresy, J. García-Lafuente and S.A. Josey. – 2006. Mediterranean sea level and barotropic flow through the strait of Gibraltar for the period 1958-2001 and reconstructed since 1659. J. Geophys. Res., 111(C11005).

Herbaut, C., F. Martel and M. Crepon. – 1997. A sensitivity study of the general circulation of the western Mediterranean Sea, the response to atmospheric forcing. J. Phys. Oceanogr., 27(10): 2126-2145. doi:10.1175/1520-0485(1997)027<2126:ASSOTG>2.0.CO;2

Herrmann, M., S. Somot, F. Sevault, C. Estournel and M. Déqué. – 2008. Modelling the deep convection in the north-western Mediterranean sea using an eddy-permitting and an eddy-resolving model: Case study of winter 1986-1987. J. Geophys. Res. C, 113(C04011).

Horton, C., M. Clifford, J. Schmitz and L.H. Kantha. – 1997. A real-time oceanographic nowcast-forecast system for the Mediterranean Sea. J. Geophys. Res. C, 102(C13): 27,991.

Josey, S.A. – 2003. Changes in the heat and freshwater forcing of the eastern Mediterranean and their influence on deep water formation. J. Geophys. Res. C, 108(C7): 3237 doi:10.1029/2003JC001778

Korres, G., N. Pinardi and A. Lascaratos. – 2000. The ocean response to low-frequency interannual atmospheric variability in the Mediterranean Sea, part I: Sensitivity experiments and energy analysis. J. Clim., 13: 705-731. doi:10.1175/1520-0442(2000)013<0705:TORTLF>2.0.CO;2

Krahmann, G. and F. Schott. – 1998. Long-term increases in western Mediterranean salinities and temperatures: Anthropogenic and climatic sources. Geophys. Res. Lett., 25(22): 4209-4212 doi:10.1029/1998GL900143

Larnicol, G., P.-Y. Le Traon, N. Ayoub, and P. De Mey. – 1995. Mean sea level and surface circulation variability of the Mediterranean Sea from 2 years of Topex/Poseidon altimetry. J. Geophys. Res. C, 100(C12): 25,163-25,177.

Le Traon, P.-Y., F. Nadal and N. Ducet. – 1998. An improved mapping method of multisatellite altimeter data. J. Atmos. Ocean Technol., 15(2): 522-534. doi:10.1175/1520-0426(1998)015<0522:AIMMOM>2.0.CO;2

Le Traon, P.-Y., Y. Faugere, F. Hernandez, J. Dorandeu, F. Mertz and M. Ablain. – 2003. Can we merge Geosat follow-on with Topex/Poseidon and ERS-2 for an improved description of the ocean circulation? J. Atmos. Ocean Technol., 20(6): 889-895. doi:10.1175/1520-0426(2003)020<0889:CWMGFW>2.0.CO;2

Leaman, K. and F. Schott. – 1991. Hydrographic structure of the convection regime in the gulf of lions - 1987. J. Phys. Oceanogr., 21(4): 575-598. doi:10.1175/1520-0485(1991)021<0575:HSOTCR>2.0.CO;2

Madec, G. – 2008. NEMO reference manual, ocean dynamic component: NEMO-OPA. Preliminary version, Tech. Rep. 27, Note du pôle de modélisation, Institut Pierre Simmon Laplace (IPSL), France, ISSN No 1288-1619.

Mariotti, A., M. Struglia, N. Zeng and K. Lau. – 2002. The hydrological cycle in the Mediterranean region and implications for the water budget of the Mediterranean Sea. J. Clim., 15(13): 1674-1690. doi:10.1175/1520-0442(2002)015<1674:THCITM>2.0.CO;2

MEDOC Group. – 1970. Observation of formation of deep water in the Mediterranean Sea in 1969. Nature, 227: 1037-1040. doi:10.1038/2271037a0

MEDAR Group. – 2002. Mediterranean and Black Sea Database of Temperature, Salinity and Biochemical Parameters and Climatological Atlas [4 CD-ROMs], Ifremer Ed., Plouzane, France. (Available at

Molines, J., A. Treguier, B. Barnier, L. Brodeau, J.L. Sommer, G. Madec, T. Penduff, S. Theetten, Y. Drillet, C. Talandier, J. Orr and Z. Lachkar. – 2006. Le modéle drakkar de la variabilité océanique globale, 1958-2004. Technical report, IDRIS.

Özsoy, E. and U. Unluata. – 1998. The Black Sea. In: The Sea, volume 11. Wiley, New York.

Pascual, A., M. Marcos and D. Gomis. – 2008. Comparing the sea level response to pressure and wind forcing of two barotropic models: Validation with tide gauge and altimetry data. J. Geophys. Res., 113(C07011).

Penduff, T., B. Barnier, A.-M. Treguier and P.-Y. Le Traon. – 2006. Synergy between ocean observations and numerical simulations: Clipper heritage and DRAKKAR perspectives. Proceedings of the symposium “15 yearsof progress in radar altimetry”, Venice, 16-18 March 2006.

Peneva, E., E. Stanev, V. Belokopytov and P.Y. Le Traon. – 2001. Water transport in the Bosphorus straits estimated from hydro-meteorological and altimeter data: seasonal to decadal variability. J. Mar. Syst., 31(1-3): 21-33. doi:10.1016/S0924-7963(01)00044-6

Pinardi, N., G. Korres, A. Lascaratos, V. Roussenov and E. Stanev. – 1997. Numerical simulation of the interannual variability of the mediterranean sea upper ocean circulation. Geophys. Res. Lett., 24(4): 425-428. doi:10.1029/96GL03952

Rixen, M., J.-M. Beckers, S. Levitus, J. Antonov, T. Boyer, C. Maillard, M. Fichaut, E. Balopoulos, S. Iona, H. Dooley, M.-J. Garcia, B. Manca, A. Giorgetti, G. Manzella, N. Mikhailov, N. Pinardi and M. Zavatarelli. – 2005. The western Mediterranean deep water: A proxy for climate change. Geophys. Res. Lett., 32(L12608).

Robinson, A., W. Leslie, A. Theocharis and A. Lascaratos. – 2001. Mediterranean Sea Circulation. In: Encyclopedia of Ocean Sciences, pp 1689–1706. Academic Press Ltd., London.

Roussenov, V., E. Stanev, V. Artale and N. Pinardi. – 1995. A seasonal model of the Mediterranean Sea general circulation. J. Geophys. Res., 100(C7): 13,515-13,538

Ruiz, S., D. Gomis, M.G. Sotillo and S.A. Josey. – 2008. Characterization of surface heat fluxes in the Mediterranean Sea from a 44-year high-resolution atmospheric data set. Global Planet. Change, 63(2-3): 258-274. doi:10.1016/j.gloplacha.2007.12.002

Salat, J. and J. Pascual. – 2006. Principales tendencias climatológicas en el mediterráneo noroccidental, a partir de más de 30 años de observaciones oceanográficas en la costa catalana. Clima, Sociedad y Medio Ambiente, A(5): 284-290.

Simmons, A. and J. Gibson. – 2000. The ERA-40 project plan. Technical Report 1, European Centre for Medium Range Weather Forecast, Reading, UK.

Somot, S., F. Sevault and M. Déqué. – 2006. Transient climate change scenario simulation of the Mediterranean Sea for the twenty-first century using a high-resolution ocean circulation model. Clim. Dyn., 27(7): 851-879. doi:10.1007/s00382-006-0167-z

Sparnocchia, S., G. Manzella and P. La Violette. – 1994. The interannual and seasonal variability of maw and LIW core properties in the western Mediterranean Sea. Coast. Estuar. Stud., 46: 177-194.

Tonani, M., N. Pinardi, S. Dobricic, I. Pujol and C. Fratianni. – 2008. A high-resolution free-surface model of the Mediterranean Sea. Ocean Sci., 4(1): 1-14. doi:10.5194/os-4-1-2008

Tsimplis, M., M. Marcos, J. Colin, S. Somot, A. Pascual and A. Shaw. – 2009. Sea level variability in the Mediterranean Sea during the 1990s on the basis of two 2D and one 3D model. J. Mar. Syst., 78(1): 109-123. doi:10.1016/j.jmarsys.2009.04.003

Tsimplis, M.N. and T.F. Baker. – 2000. Sea level drop in the Mediterranean Sea: An indicator of deep water salinity and temperature changes? Geophys. Res. Lett., 27(12): 1731-1734. doi:10.1029/1999GL007004

Tsimplis, M.N. and H.L. Bryden. – 2000. Estimation of the transports through the strait of Gibraltar. Deep-Sea Res., 47(I): 2219-2242.

Tsimplis, M.N., M. Marcos, S. Somot and B. Barnier. – 2008. Sea level forcing in the Mediterranean Sea between 1960 and 2000. Global Planet. Change, 63(4): 325-332. doi:10.1016/j.gloplacha.2008.07.004

Tsimplis, M.N. and M. Rixen. – 2002. Sea level in the Mediterranean Sea: The contribution of temperature and salinity changes. Geophys. Res. Lett., 29(23): 2136 doi:10.1029/2002GL015870

Unluata, U., T. Oguz, M. Latif and E. Özsoy. – 1990. On the physical oceanography of the Turkish Straits. In: The Physical Oceanography of Sea Straits, pp 25-60. Kluwer Academic Publishing.

Vargas-Yáñez, M., F. Moya, E. Tel, M.C. García-Martínez, E. Guerber and M. Bourgeon. – 2009. Warming and salting in the western Mediterranean during the second half of the 20th century: inconsistencies, unknowns and the effect of data processing. Sci. Mar., 73(1): 7-28.

Woolfe, D., A. Shaw and M.N. Tsimplis. – 2003. The influence of the North Atlantic Oscillation on sea-level variability in the North Atlantic region. J. Atmos. Ocean Sci., ¡ 9(4): 145-167.

Wu, P. and K. Haines. – 1998. The general circulation of the Mediterranean Sea from a 100-year simulation. J. Geophys. Res., 103(C1): 1121-1135 doi:10.1029/97JC02720

Wüst, G. – 1961. On the vertical circulation of the Mediterranean Sea. J. Geophys. Res., 66(10): 3261-3271.

Zavatarelli, M. and G. Mellor. – 1995. A numerical study of the Mediterranean Sea circulation. J. Phys. Oceanogr., 25(6 (2)): 1384-1414.

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