Advertisement

Climate Dynamics

, Volume 48, Issue 3–4, pp 851–865 | Cite as

Reconstruction of transports through the Strait of Gibraltar from limited observations

  • G. Jordà
  • A. Sánchez-Román
  • D. Gomis
Article

Abstract

Observing the water transports through the Strait of Gibraltar is a difficult task. Here we present a methodology aimed to obtain the inflow, outflow and net transport of water from the limited set of available observations, currently consisting of an upward looking ADCP deployed at Espartel sill, two tide gauges located at each side of the Strait and radars monitoring the surface velocities. More precisely, we reconstruct the velocity field over a vertical section across the Strait using a reduced order optimal interpolation technique fed with the spatial covariance patterns deduced from high resolution numerical simulations. As a first step we carry out some sensitivity experiments with synthetic data that demonstrate the high potential of the approach. The reconstruction methodology can reproduce very satisfactorily the variability of the transports with estimated correlations for the inflow, outflow and net over 0.9 in all the cases and estimated RMS errors of 0.03, 0.08 and 0.05 Sv, respectively. However, we have also found that the reconstruction is sensible to bias problems, mostly due to the sensitivity of the method to the differences between the statistics of the actual and modeled velocity profiles. The sensitivity experiments have been used to tune the parameters of the method and a reconstruction of actual monthly transports has been performed for the period 2004–2010 along with an estimate of the associated uncertainty. This reconstruction provides for the first time a multiannual time series of the inflow and the net transports solely based on in situ observations. Therefore it can be used as an independent estimate for the validation of numerical models and surface freshwater fluxes in the Mediterranean.

Keywords

Gibraltar Strait Mediterranean Sea Transports Reconstruction 

Notes

Acknowledgments

G. Jordà acknowledges a Ramón y Cajal contract (RYC-2013-14714) funded by the Spanish Ministry of Economy and the Regional Government of the Balearic Islands; he also acknowledges a post-doctoral Grant Funded by the Regional Government of the Balearic Islands and the European Social Fund. A. Sánchez-Román acknowledges a Juan de la Cierva contract (JCI-2011-10196) funded by the Spanish Ministry of Economy and Competitiveness. The authors thank J. Polcher for the river runoff datasets, the Permanent Service for Mean Sea Level (www.psmsl.org) for making available the tide gauge data and J. García-Lafuente for the ADCP data of the Espartel monitoring station, which were collected in the frame of the Spanish Funded projects INGRES (REN2003-01608/MAR), INGRES2 (CTM2006-02326/MAR), INGRES3 (CTM2010-21229-C02-01/MAR) and CTM2009-05810-E/MAR. We also thank Diego Fernandez and the European Space Agency for partially funding this study under the project « ESA WACMOS Mediterranean » (No. 4000114770/15/I-SBo). The reconstructed transports and the indirect estimate of the net transport presented here are available at http://marine-climate.uib.es.

References

  1. Álvarez Fanjul E, Gómez BP, Sánchez Arévalo IR (2001) Nivmar: a storm surge forecasting system for the Spanish waters. Sci Mar 65:145–154. doi: 10.3989/scimar.2001.65s1145 CrossRefGoogle Scholar
  2. Armi L, Farmer DM (1988) The flow of Mediterranean water through the Strait of Gibraltar. Prog Oceanogr 21:1–105CrossRefGoogle Scholar
  3. Boutov D, Peliz A, Miranda PMA, Soares PMM, Cardoso RM (2014) Inter-annual variability and long term predictability of exchanges through the Strait of Gibraltar. Glob Planet Change 114:23–37. doi: 10.1016/j.gloplacha.2013.12.009 CrossRefGoogle Scholar
  4. Bryden H, Candela J, Kinder T (1994) Exchange through the Strait of Gibraltar. Prog Oceanogr 33(3):201–248CrossRefGoogle Scholar
  5. Calafat FM, Chambers DP, Tsimplis MN (2014) On the ability of global sea level reconstructions to determine trends and variability. J Geophys Res Oceans 119:1572–1592. doi: 10.1002/2013JC009298 CrossRefGoogle Scholar
  6. Candela J (2001) Mediterranean water and global circulation. In: Siedler G, Church J, Gould J (eds) Ocean circulation and climate. Academic, San Diego, pp 419–429Google Scholar
  7. Candela J, Winant C, Ruiz A (1990) Tides in the Strait of Gibraltar. J Geophys Res 95(C5):7313–7335CrossRefGoogle Scholar
  8. Carrère L, Lyard F (2003) Modeling the barotropic response of the global ocean to atmospheric wind and pressure forcing-comparisons with observations. Geophys Res Lett 30:1275. doi: 10.1029/2002GL016473 CrossRefGoogle Scholar
  9. Criado-Aldeanueva J, Soto-Navarro FJ, García-Lafuente J (2012) Seasonal and interannual variability of surface heat and freshwater fluxes in the Mediterranean Sea: budgets and exchange through the Strait of Gibraltar. Int J Climatol 32:286–302. doi: 10.1002/joc.2268 CrossRefGoogle Scholar
  10. García-Lafuente J, Vargas J, Plaza F, Sarhan T, Candela J, Bascheck B (2000) Tide at the eastern section of the Strait of Gibraltar. J Geophys Res 105(C6):14197–14213CrossRefGoogle Scholar
  11. García-Lafuente J, Alvarez-Fanjul E, Vargas J, Ratsimandresy A (2002) Subinertial variability through the Strait of Gibraltar. J Geophys Res 107(C10):3168. doi: 10.1029/2001JC001104 CrossRefGoogle Scholar
  12. Harzallah A, Alioua M, Li L (2014) Mass exchange at the Strait of Gibraltar in response to tidal and lower frequency forcing as simulated by a Mediterranean Sea model. Tellus A 66:23871. doi: 10.3402/tellusa.v66.23871 CrossRefGoogle Scholar
  13. Herrmann M, Somot S, Calmanti S, Dubois C, Sevault F (2011) Representation of spatial and temporal variability of daily wind speed and of intense wind events over the Mediterranean Sea using dynamical downscaling: impact of the regional climate model configuration. Nat Hazards Earth Syst Sci 11:1983–2001. doi: 10.5194/nhess-11-1983-2011 CrossRefGoogle Scholar
  14. Hughes CW, Bingham RJ, Roussenov V, Williams J, Woodworth PL (2015) The effect of Mediterranean exchange flow on European time mean sea level. Geophys Res Lett 42:466–474. doi: 10.1002/2014GL062654 CrossRefGoogle Scholar
  15. Ishii M, Kimoto M (2009) Reevaluation of historical ocean heat content variations with time-varying XBT and MBT depth bias corrections. J Oceanogr 65:287–299CrossRefGoogle Scholar
  16. Jordà G, Gomis D (2013a) Reliability of the steric and mass components of Mediterranean Sea level as estimated from hydrographic gridded products. Geophys Res Lett 40:3655–3660. doi: 10.1002/grl.50718 CrossRefGoogle Scholar
  17. Jordà G, Gomis D (2013b) On the interpretation of the steric and mass components of sea level variability: the case of the Mediterranean basin. J Geophys Res Oceans 118:953–963. doi: 10.1002/jgrc.20060 CrossRefGoogle Scholar
  18. Kaplan A, Kushnir Y, Cane MA, Blumenthal MB (1997) Reduced space optimal analysis for historical data sets: 136 years of Atlantic sea surface temperatures. J Geophys Res 102:27835–27860CrossRefGoogle Scholar
  19. Kaplan A, Cane MA, Kushnir Y, Clement AC, Blumenthal MB, Rajagopalan B (1998) Analyses of global sea surface temperature 1856–1991. J Geophys Res 103(C9):18567–18589. doi: 10.1029/97JC01736 CrossRefGoogle Scholar
  20. Kaplan A, Kushnir Y, Cane MA (2000) Reduced space optimal interpolation of historical marine sea level pressure: 1854–1992. J Clim 13:2987–3002CrossRefGoogle Scholar
  21. Krinner G, Viovy N, de-Noblet-Ducoudré N, Ogée J, Polcher J, Friedlingstein P, Ciais P, Sitch S, Prentice C (2005) A dynamic global vegetation model for studies of the coupled atmosphere-biosphere system. Glob Change Biol 19:1015–1048Google Scholar
  22. Lorente P, Soto-Navarro J, Alvarez Fanjul E, Piedracoba S (2014) Accuracy assessment of high frequency radar current measurements in the Strait of Gibraltar. J Oper Oceanogr 7(2):59–73CrossRefGoogle Scholar
  23. Ludwig W, Dumont E, Meybeck M, Heussner S (2009) River discharges of water and nutrients to the Mediterranean and Black Sea: major drivers for ecosystem changes during past and future decades? Prog Oceanogr 80(3–4):199–217CrossRefGoogle Scholar
  24. Marshall J, Hill C, Perelman L, Adcroft A (1997a) Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling. J Geophys Res 102(C3):5733–5752. doi: 10.1029/96JC02776 CrossRefGoogle Scholar
  25. Marshall J, Adcroft A, Hill C, Perelman L, Heisey C (1997b) A finite-volume, incompressible Navier Stokes model for studies of the ocean on parallel computers. J Geophys Res 102:5753–5766. doi: 10.1029/96JC02775 CrossRefGoogle Scholar
  26. Ngo-Duc T, Laval K, Ramillien G, Polcher J, Cazenave A (2006) Validation of the land water storage simulated by ORCHIDEE with the GRACE data, role of the routing scheme. Water Resour Res 43(4):W04427. doi: 10.1029/2006WR004941 Google Scholar
  27. Ross T, Garrett C, Le Traon PY (2000) Western Mediterranean Sea-level rise: changing exchange flow through the Strait of Gibraltar. Geophys Res Lett 27(18):2949–2952. doi: 10.1029/2000GL011653 CrossRefGoogle Scholar
  28. Sammartino S, Garcia-Lafuente J, Sanchez-Garrido JC, De los Santos FJ, Álvarez-Fanjul E, Naranjo C, Bruno M, Calero C (2014) A numerical model analysis of the tidal flows in the Bay of Algeciras, Strait of Gibraltar. Cont Shelf Res 72:34–46. doi: 10.1016/j.csr.2013.11.002 CrossRefGoogle Scholar
  29. Sanchez-Garrido JC, Garcia-Lafuente J, Alvarez-Fanjul E, Sotillo M, de-los-Santos FJ (2013) What does cause the collapse of the Western Alboran Gyre? results of an operational ocean model. Prog Oceanogr 116:142–153. doi: 10.1016/j.pocean.2013.07.002 CrossRefGoogle Scholar
  30. Sanchez-Roman A, Sannino G, Garcia-Lafuente J, Carillo A, Criado-Aldeanueva F (2009) Transport estimates at the western section of the Strait of Gibraltar: a combined experimental and numerical modeling study. J Geophys Res 114:C06002. doi: 10.1029/2008JC005023 CrossRefGoogle Scholar
  31. Sevault F, Somot S, Alias A, Dubois C, Lebeaupin-Brossier C, Nabat P, Adloff F, Déqué M, Decharme B (2014) A fully coupled Mediterranean regional climate system model: design and evaluation of the ocean component for the 1980–2012 period. Tellus A 66:23967. doi: 10.3402/tellusa.v66.23967 CrossRefGoogle Scholar
  32. Sotillo MG, Cailleau S, Lorente P, Levier B, Aznar R, Reffray G, Amo-Baladrón A, Chanut J, Benkiran M, Alvarez-Fanjul E (2015) The MyOcean IBI ocean forecast and reanalysis systems: operational products and roadmap to the future Copernicus service. J Oper Oceanogr 8(1):63–79. doi: 10.1080/1755876X.2015.1014663 CrossRefGoogle Scholar
  33. Soto-Navarro J, Criado-Aldeanueva F, García-Lafuente J, Sánchez-Román A (2010) Estimation of the Atlantic inflow through the Strait of Gibraltar from climatological and in situ data. J Geophys Res 115:C10023. doi: 10.1029/2010JC006302 CrossRefGoogle Scholar
  34. Stanev EV, Peneva EL (2002) Regional sea level response to global climatic change: Black Sea examples. Glob Planet Change 32:33–47CrossRefGoogle Scholar
  35. Tsimplis MN, Bryden HL (2000) Estimation of the transport through the Strait of Gibraltar. Deep Sea Res Part I 47:2219–2242CrossRefGoogle Scholar
  36. Vargas J, García-Lafuente J, Candela J, Sanchez A (2006) Fortnightly and monthly variability of the exchange through the Strait of Gibraltar. Prog Oceanogr 70(2–4):466–485CrossRefGoogle Scholar
  37. Weedon GP, Balsamo G, Bellouin N, Gomes S, Best MJ, Viterbo P (2014) The WFDEI meteorological forcing data set: WATCH forcing data methodology applied to ERA-interim reanalysis data. Water Resour Res 50:7505–7514. doi: 10.1002/2014WR015638 CrossRefGoogle Scholar
  38. Woodworth PL, Player R (2003) The permanent service for mean sea level: an update to the 21st century. J Coast Res 19:287–295Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Institut Mediterrani d’Estudis Avançats (IMEDEA, UIB-CSIC)EsporlesSpain

Personalised recommendations