The Mediterranean Outflow Water: Transformations and Pathways Into the Gulf of Cádiz
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Interannual Variability of the Mediterranean Outflow Observed in Espartel Sill, Western Strait of Gibraltar J
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114, C10018, doi:10.1029/2009JC005496, 2009 Interannual variability of the Mediterranean outflow observed in Espartel sill, western Strait of Gibraltar J. Garcı´a-Lafuente,1 J. Delgado,1 A. Sa´nchez Roma´n,1 J. Soto,1 L. Carracedo,1,2 and G. Dı´az del Rı´o3 Received 6 May 2009; revised 13 July 2009; accepted 24 July 2009; published 22 October 2009. [1] Four-year time series of observations in Espartel sill at the western part of the Strait of Gibraltar have been analyzed in order to investigate the variability of the Mediterranean outflow. It is assumed that the observed variability comes from the changing properties of the dense waters that are located at the maximum depth from where they can be uplifted in the upstream basin (Albora´n Sea, inside the Mediterranean Sea) and evacuated through the strait. From this perspective, the following three mechanisms are investigated: (1) the replenishment of the deep basin by newly formed Western Mediterranean Deep Water that, depending on its density, can either uplift old resident waters or lay above them leaving in any case a cold signature in the temperature series; (2) the presence/absence of the energetic anticyclonic gyres in the Albora´n Sea, particularly the western one, which can transfer momentum to the underlying Mediterranean vein and provide it with additional energy to ascend over the sills of the strait; and (3) the meteorologically enhanced flows that follow the rapid changes of atmospheric pressure over the western Mediterranean basin, which would be able to aspire deeper waters residing in the upstream basin. -
Improved Modelling of the Messinian Salinity Crisis and Conceptual Implications
Palaeogeography, Palaeoclimatology, Palaeoecology 238 (2006) 349–372 www.elsevier.com/locate/palaeo Improved modelling of the Messinian Salinity Crisis and conceptual implications Paul-Louis Blanc Institut de Radioprotection et de Sûreté Nucléaire, Boîte Postale 17, 92262 Fontenay-aux-roses Cedex, France Received 17 April 2003; accepted 7 March 2006 Abstract This paper presents the last developments of a simple oceanographic modelling of the water and salt budgets of the Mediterranean Sea during the late Miocene Salinity Crisis. The Messinian Mediterranean is treated as analogous to the present one, i.e. divided into two main basins separated by a sill at shallow or intermediate depth. When the supply of marine water from the Atlantic is progressively reduced, both basins undergo a rise in salinity, until saturation is reached: this is when the true evaporitic sedimentation begins, before the level drawdown. The partition of the Mediterranean into two mains basins causes a shift in the evaporitic sedimentation from the distal (eastern) basin to the proximal (western) basin, so that the evaporitic deposits are not fully contemporaneous in the western and the eastern basin. The drawdown is limited by the equilibrium of the evaporation and chemical activity of the brines at the surface, against the surface area and evaporation. Attempts at adjusting the model both to an accurate stratigraphic frame and to a rough budget of the evaporites shows that the Upper Evaporites and brackish-water Lago-mare series must have been deposited as secondary deposits, after the closure of the Atlantic passages was completed. The present evaporitic potentialities of the Mediterranean Sea remains quite as strong as during the Miocene, so that climatic change cannot be inferred from the MSC itself. -
On the Connection Between the Mediterranean Outflow and The
FEBRUARY 2001 OÈ ZGOÈ KMEN ET AL. 461 On the Connection between the Mediterranean Out¯ow and the Azores Current TAMAY M. OÈ ZGOÈ KMEN,ERIC P. C HASSIGNET, AND CLAES G. H. ROOTH RSMAS/MPO, University of Miami, Miami, Florida (Manuscript received 18 August 1999, in ®nal form 19 April 2000) ABSTRACT As the salty and dense Mediteranean over¯ow exits the Strait of Gibraltar and descends rapidly in the Gulf of Cadiz, it entrains the fresher overlying subtropical Atlantic Water. A minimal model is put forth in this study to show that the entrainment process associated with the Mediterranean out¯ow in the Gulf of Cadiz can impact the upper-ocean circulation in the subtropical North Atlantic Ocean and can be a fundamental factor in the establishment of the Azores Current. Two key simpli®cations are applied in the interest of producing an eco- nomical model that captures the dominant effects. The ®rst is to recognize that in a vertically asymmetric two- layer system, a relatively shallow upper layer can be dynamically approximated as a single-layer reduced-gravity controlled barotropic system, and the second is to apply quasigeostrophic dynamics such that the volume ¯ux divergence effect associated with the entrainment is represented as a source of potential vorticity. Two sets of computations are presented within the 1½-layer framework. A primitive-equation-based com- putation, which includes the divergent ¯ow effects, is ®rst compared with the equivalent quasigeostrophic formulation. The upper-ocean cyclonic eddy generated by the loss of mass over a localized area elongates westward under the in¯uence of the b effect until the ¯ow encounters the western boundary. -
UTMEA, Rome University of Malaga (Spain)
Symposium on HPC And Data-Intensive Applications In Earth Sciences: Challenges and Opportunities 13 Nov. 2014 Gianmaria Sannino+, A. Carillo+, G. Pisacane+, C. Naranjo° ENEA - UTMEA, Rome University of Malaga (Spain) Energy and Environmental Modelling Unit [email protected] Italian Agency for New Technologies, Energy and Sustainable Economic Development NEMERTE – Numerical Experiment on the Mediterranean model response to Enhanced Resolution and TidE Project leader: Gianmaria Sannino, ENEA, ITALY Collaborators: Patrick Heimbach, Massachusetts Institute of Technology (MIT), UNITED STATES Gabriel Jorda Sanchez, Mediterranean Institute for Advanced Studies (IMEDEA), SPAIN Vincenzo Artale, ENEA, Italy Adriana Carillo, ENEA, Italy Emanuele Lombardi, ENEA, Italy Giovanna Pisacane, ENEA, Italy MariaVittoria Struglia, ENEA, Italy FERMI@CINECA NEMERTE Resource Awarded: 18 Million core hours on FERMI Architecture: 10 BGQ Frames Model: IBM-BG/Q Processor type: IBM PowerA2 @1.6 GHz Computing Cores: 163840 Computing Nodes: 10240 RAM: 1GByte / core (163 PByte total) Internal Network: 5D Torus Disk Space: 2PByte of scratch space Peak Performance: 2PFlop/s N. 7 in Top 500 rank (June 2012) National and PRACE Tier-0 calls The mission of PRACE (Partnership for Advanced Computing in Europe) is to enable high impact scientific discovery and engineering research and development across all disciplines to enhance European competitiveness for the benefit of society. PRACE seeks to realize this mission by offering world class computing and data management resources and services through a peer review process. OUTLINE HOW DID NEMERTE BEGIN? A fascinang story involving ocean models and HPC Mediterranean Thermohaline Circulation (MTHC) The Mediterranean Sea is a semi-enclosed basin displaying an active thermohaline circulation that is sustained by the atmospheric forcing and controlled by the narrow and shallow Strait of Gibraltar The atmospheric forcing drives the Mediterranean basin toward a negative budget of water and heat, and toward a positive budget of salt. -
The Role of Tides in the Spreading of Mediterranean Outflow Waters
Ocean Modelling 133 (2019) 27–43 Contents lists available at ScienceDirect Ocean Modelling journal homepage: www.elsevier.com/locate/ocemod The role of tides in the spreading of Mediterranean Outflow waters along the T southwestern Iberian margin ⁎ Alfredo Izquierdoa, , Uwe Mikolajewiczb a Applied Physics Department, University of Cádiz, CEIMAR, Cádiz, Spain, Avda. República Saharahui s/n, CASEM 11510, Puerto Real, Cádiz, Spain b Max Planck Institute for Meteorology, Hamburg, Germany, Bundesstraße 53, Hamburg 20146, Germany ABSTRACT The impact of tides on the spreading of the Mediterranean Outflow Waters (MOW) in the Gulf of Cadiz is investigated through a series of targeted numerical experiments using an ocean general circulation model. The full ephimeridic luni-solar tidal potential is included as forcing. The model grid is global with a strong zoom around the Iberian Peninsula. Thus, the interaction of processes of different space and time scales, which are involved in the MOW spreading, is enabled. Thisis of particular importance in the Strait of Gibraltar and the Gulf of Cádiz, where the width of the MOW plume is a few tens of km. The experiment with enabled tides successfully simulates the main tidal features of the North Atlantic and in the Gulf of Cádiz and the Strait of Gibraltar. The comparison of the fields from simulations with and without tidal forcing shows drastically different MOW pathways in the Gulf of Cádiz: The experiment without tides shows an excessive southwestward spreading of Mediterranean Waters along the North African slope, whereas the run with tides is closer to climatology. A detailed analysis indicates that tidal residual currents in the Gulf of Cádiz are the main cause for these differences. -
A Parallel 2D Finite Volume Scheme for Solving Systems of Balance Laws
Comput. Methods Appl. Mech. Engrg. 195 (2006) 2788–2815 www.elsevier.com/locate/cma A parallel 2d finite volume scheme for solving systems of balance laws with nonconservative products: Application to shallow flows M.J. Castro a,*, J.A. Garcı´a-Rodrı´guez a, J.M. Gonza´lez-Vida b, C. Pare´s a a Dpto. de Ana´lisis Matema´tico, Universidad de Ma´laga, Campus Teatinos s/n, 29071 Ma´laga, Spain b Dpto. de Matema´tica Aplicada, Universidad de Ma´laga, Spain Received 20 January 2005; received in revised form 1 July 2005; accepted 5 July 2005 Abstract The goal of this paper is to construct parallel solvers for 2d hyperbolic systems of conservation laws with source terms and nonconservative products. More precisely, finite volumes solvers on nonstructured grids are considered. The method of lines is applied: at every intercell a projected Riemann problem along the normal direction is considered which is discretized by means of the numerical schemes presented in [M.J. Castro, J. Macı´as, C. Pare´s. A Q-scheme for a class of systems of coupled conservation laws with source term. Application to a two-layer 1-D shallow water system, ESAIM: M2AN 35 (1) (2001) 107–127]. The resulting 2d numerical schemes are explicit and first order accurate. The solver is next parallelized by a domain decomposition technique. The specific application of the scheme to one- and two- layer shallow water systems has been implemented on a PCÕs cluster. An efficient data structure based on OOMPI (C++ object oriented extension of MPI) has been developed to optimize the data exchange among the processors. -
Global Ocean Meridional Overturning
2550 JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME 37 NOTES AND CORRESPONDENCE Global Ocean Meridional Overturning RICK LUMPKIN Physical Oceanography Division, NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida KEVIN SPEER Department of Oceanography, The Florida State University, Tallahassee, Florida (Manuscript received 9 August 2005, in final form 9 January 2007) ABSTRACT A decade-mean global ocean circulation is estimated using inverse techniques, incorporating air–sea fluxes of heat and freshwater, recent hydrographic sections, and direct current measurements. This infor- mation is used to determine mass, heat, freshwater, and other chemical transports, and to constrain bound- ary currents and dense overflows. The 18 boxes defined by these sections are divided into 45 isopycnal (neutral density) layers. Diapycnal transfers within the boxes are allowed, representing advective fluxes and mixing processes. Air–sea fluxes at the surface produce transfers between outcropping layers. The model obtains a global overturning circulation consistent with the various observations, revealing two global-scale meridional circulation cells: an upper cell, with sinking in the Arctic and subarctic regions and upwelling in the Southern Ocean, and a lower cell, with sinking around the Antarctic continent and abyssal upwelling mainly below the crests of the major bathymetric ridges. 1. Introduction (WGASF 2001; Garnier et al. 2000; Josey 2001; Josey et al. 1999). The global pattern of wind and heat gain and Wind, and heat and freshwater fluxes at the ocean loss in these products is qualitatively consistent in the surface are, together with tidal and other energy Northern Hemisphere where the ocean gains heat in sources, responsible for the global ocean circulation, the Tropics and loses large amounts of heat in the mixing, and the formation of a broad range of water northern North Atlantic. -
High Seas Mediterranean Marine Reserves: a Case Study for the Southern Balearics and the Sicilian Channel
High Seas Mediterranean Marine Reserves: a case study for the Southern Balearics and the Sicilian Channel A briefing to the CBD’s Expert workshop on scientific and technical guidance on the use of biogeographic classification systems and identification of marine areas beyond national jurisdiction in need of protection Ottawa, 29 September–2 October 2009 Greenpeace International August 2009 Table of Contents Table of Contents...........................................................................................................2 Abbreviations and Acronyms ........................................................................................4 Executive Summary.......................................................................................................5 1. Introduction................................................................................................................8 2. Existing research on the areas and availability of information................................10 3. Southern Balearics ...................................................................................................11 3.1 Area description.................................................................................................11 3.1.1 Main topographic features..........................................................................11 3.1.2. Currents and nutrients circulation system.................................................12 3.2 Topographic Features of Remarkable Biological relevance..............................14 3.2.1. Seamounts -
Oceanographic Processes and Morphosedimentary Products Along the Iberian Margins: a New Multidisciplinary Approach
Marine Geology 378 (2016) 127–156 Contents lists available at ScienceDirect Marine Geology journal homepage: www.elsevier.com/locate/margo Oceanographic processes and morphosedimentary products along the Iberian margins: A new multidisciplinary approach F. Javier Hernández-Molina a,⁎, Anna Wåhlin b,MiguelBrunoc, Gemma Ercilla d, Estefanía Llave e, Nuno Serra f, Gabriel Rosón g,PerePuigd, Michele Rebesco h, David Van Rooij i,DavidRoquej, César González-Pola k, Francisco Sánchez l,MaríaGómezm,BenedictPreun, Tilmann Schwenk o, Till J.J. Hanebuth p,q, Ricardo F. Sánchez Leal r, Jesús García-Lafuente s, Rachel E. Brackenridge t,u,CarmenJuand,i, Dorrik A.V. Stow t,JoséMaríaSánchez-Gonzálezg a Dept. Earth Sciences, Royal Holloway Univ. London, Egham, Surrey TW20 0EX, UK b Department of Earth Sciences, University of Gothenburg, PO Box 460, SE 405 30 Göteborg, Sweden c CACYTMAR. Univ. Cádiz, Avda República Saharaui S/N, Puerto Real, 11510, Cádiz, Spain d CSIC, ICM, Paseo Marítimo de la Barceloneta, 37-49, 08003 Barcelona, Spain e Instituto Geológico y Minero de España Ríos Rosas, 23, 28003, Madrid, Spain f Institut für Meereskunde, Univ. Hamburg, Bundesstr. 53, 20146, Hamburg, Germany g Facultad de Ciencias do Mar, Univ. Vigo, 36200 Vigo, Spain h OGS, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Borgo Grotta Gigante 42/C, 34010 Sgonico, TS, Italy i Renard Centre of Marine Geology, Dept. of Geology and Soil Science. Ghent University, Krijgslaan, 281 S8 B-9000 Gent, Belgium j CSIC, ICMAN, Campus Universitario Rio San Pedro s/n. Puerto Real, Cádiz, CP 11510, Spain k Instituto Español de Oceanografía, C.O. Gijón. c/ Príncipe de Asturias 70 Bis., CP 33212, Gijón, Spain l Instituto Español de Oceanografía, C.O. -
Mediterranean Water Properties at the Eastern Limit of the North Atlantic Subtropical Gyre Since 1981
Article Mediterranean Water Properties at the Eastern Limit of the North Atlantic Subtropical Gyre since 1981 Helena C. Frazão * and Joanna J. Waniek Leibniz Institute for Baltic Sea Research Warnemünde, Seestraße 15, 18119 Rostock, Germany; [email protected] * Correspondence: [email protected] Abstract: A high-quality hydrographic CTD and Argo float data was used to study the property changes along the westward branch of the Mediterranean Outflow Water (MOW) in the northeast Atlantic between 1981 and 2018. In this period, the temperature and salinity are marked by periods of cooling/freshening and warming/salinification. Since 1981, the MOW properties at the core decreased by −0.015 ± 0.07 ◦C year−1 and −0.003 ± 0.002 year−1. The different phases of the North Atlantic Oscillation (NAO) influence the main propagation pathways of the MOW into the North Atlantic basin, thus affecting the trends determined within different NAO-phases. The temperature and salinity show a strong correlation with NAO, with NAO leading the properties by 8 and 7 years, respectively, indicating a delayed response of the ocean to different forcing conditions. A decrease in oxygen concentration (−0.426 ± 0.276 µmol kg−1 year−1) was calculated for the same period; however, no connection with the NAO was found. Keywords: Mediterranean Outflow Water; North Atlantic Oscillation; Northeast Atlantic; time-series Citation: Frazão, H.C.; Waniek, J.J. Mediterranean Water Properties at 1. Introduction the Eastern Limit of the North The Mediterranean Water flows out of the Strait of Gibraltar and mixes with the Atlantic Subtropical Gyre since 1981. -
The Western Alboran Gyre Helps Ventilate the Western Mediterranean Deep Water Through Gibraltar
Deep-Sea Research I 63 (2012) 157–163 Contents lists available at SciVerse ScienceDirect Deep-Sea Research I journal homepage: www.elsevier.com/locate/dsri Note The Western Alboran Gyre helps ventilate the Western Mediterranean Deep Water through Gibraltar Cristina Naranjo n, Jesu´ s Garcı´a Lafuente, Jose C. Sa´nchez Garrido, Antonio Sa´nchez Roma´n, Javier Delgado Cabello Physical Oceanography Group, ETSI Telecomunicacio´n, University of Ma´laga, Campus Teatinos, 29071 Ma´laga, Spain article info abstract Article history: Variable properties of the Mediterranean outflow and the variability of the Western Alboran Gyre are Received 27 April 2011 analyzed by means of 5-year long time series of near bottom potential temperature at Espartel sill in Received in revised form the Strait of Gibraltar and altimetry data in the Alboran Sea. Geostrophic velocity at the southern edge 19 October 2011 of the gyre and potential temperature at Espartel sill are significantly correlated (correlation coefficient Accepted 24 October 2011 0.67), suggesting that the intensification of the Alboran Gyre favors the ventilation of Western Available online 29 October 2011 Mediterranean Deep Water. The analysis of historical temperature profiles shows that Western Keywords: Mediterranean Deep Water in the Alboran Sea can be suctioned from a layer between 500 and Western Mediterranean Deep Water 700 m depth for typical changes of the gyre intensification. Deep water ventilation & 2011 Elsevier Ltd. All rights reserved. Strait of Gibraltar Alboran Gyre 1. Introduction approach of the Strait and to bring them west of CS into the Atlantic Ocean. Actually, the ventilation of WMDW would comprise two The question of how the Western Mediterranean Deep Water separated, though linked, set of processes. -
Modelling Study of Transformations of the Exchange Flows Along the Strait of Gibraltar
Ocean Sci., 14, 1547–1566, 2018 https://doi.org/10.5194/os-14-1547-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Modelling study of transformations of the exchange flows along the Strait of Gibraltar Antonio Sanchez-Roman1, Gabriel Jorda1,3, Gianmaria Sannino2, and Damia Gomis1 1Institut Mediterrani d’Estudis Avançats, IMEDEA (UIB-CSIC), Mallorca, Spain 2ENEA – Climate Modelling Laboratory, Rome, Italy 3Instituto Español de Oceanografía, Centre Oceanogràfic de Balears (IEO-COB), Moll de Ponent s/n 07015, Palma, Spain Correspondence: Antonio Sánchez-Román ([email protected]) Received: 3 May 2018 – Discussion started: 4 June 2018 Revised: 30 October 2018 – Accepted: 21 November 2018 – Published: 18 December 2018 Abstract. Vertical transfers of heat, salt and mass between 1 Introduction the inflowing and outflowing layers at the Strait of Gibral- tar are explored basing on the outputs of a three-dimensional The Strait of Gibraltar is a narrow and shallow channel with fully nonlinear numerical model. The model covers the entire a length of about 60 km and a mean width of 20 km that Mediterranean basin and has a very high spatial resolution presents a complex system of contractions and submarine around the strait (1/200◦). Another distinctive feature of the sills (see Fig. 1). Between Gibraltar and Ceuta, the channel is model is that it includes a realistic barotropic tidal forcing about 25 km wide and 800–900 m deep; west of this section (diurnal and semi-diurnal), in addition to atmospheric pres- the strait narrows towards a minimum cross section of about sure and heat and water surface fluxes.