Circulation and mixing of Mediterranean water west of the Iberian Peninsula

Daniault, Nathalie; Mazé, Jean‐Pierre; Arhan, Michel

doi:10.1016/0967-0637(94)90068-x

Cited by 91 publications

(66 citation statements)

References 27 publications

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“…5d). In the vertical, the influence of the MW extends to at least 2000 m (Reid, 1978;Harvey, 1982;Daniault et al, 1994). The colder water plume at the eastern slope of the MAR below 1500 m corresponds to the southward penetration of Labrador Sea Water (LSW) into the eastern subtropical Atlantic (Bower et al, 2002).…”

Section: Resultsmentioning

confidence: 99%

Temperature–salinity distribution in the northeastern Atlantic from ship and Argo vertical casts

et al. 2015

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Abstract. The present study defines new interpolation functions for hydrological data. These functions are applied to generate climatological maps of temperature-salinity distribution with a 25 m depth interval and a 30 km space interval (MEDTRANS data set). The data undergo rigorous initial data quality control, having passed several filtering procedures. The gridding is done on neutral density surfaces, which allows better representation of thermohaline fronts for the same gridding radius. The multi-pass Barnes optimum interpolation procedure with spatially variable size of the gridding window is used. The shape of the window accounts for the dominant along-isobath direction of water mass transport over steeply sloping topography. A local ratio of topographic to planetary β-effects is used to define the shape of the window as a function of the relative importance of the topographic influence. The N /f ratio is applied to account for the baroclinic compensation decay of the topographic influence on water mass transport with the distance from the bottom. The gridded fields are available at the website of the Centre of Oceanography of the University of Lisbon (http://co.fc.ul.pt/en/data).The MEDTRANS climatology gives more details of the distribution of water characteristics in the subtropical northeastern Atlantic than other alternative climatologies and is able to reproduce a number of dynamic features described in the literature: the acceleration in the meanders of the Azores current; the cyclonic gyre in the Gulf of Cadiz; and the splitting and separation of the Mediterranean Water (MW) outflow in two veins near the Gorringe and Galicia banks. Seasonal climatologies, computed for the warm (May-October) and cold (November-April) seasons, reveal stronger zonal extension of the upper ocean patterns during the warm season, as compared to the cold one.

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Section: Resultsmentioning

confidence: 99%

Temperature–salinity distribution in the northeastern Atlantic from ship and Argo vertical casts

et al. 2015

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“…This corresponds to intense entrainment, mixing and vertical diffusion between the water masses. In particular, the influence of the MW extends down to temperatures as low as 5.0˚C, due to vertical diffusion [4].…”

Section: Water Massesmentioning

confidence: 99%

“…These three cores are strongly steered by the regional bathymetry and flow firstly westward along the Iberian southern continental slope and then northward along the Iberian western continental slope. Along their way, the MW cores undergo entrainment and mixing with the upper North Atlantic Central Water, as indicated by the progressive loss of depth of the MW cores along the west Iberian coast [4]. In the Gulf of Cadiz, the steep bathymetry, the density gradients and the turbulent fluxes force currents to recirculate horizontally, mostly cyclonically [5].…”

Section: Introduction and Data Collectionmentioning

confidence: 99%

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

Alves¹,

Carton²,

Ambar³

2011

IJG

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Hydrological and LADCP data from four experiments at sea (Semane 1999(Semane , 2000(Semane /1, 2000(Semane /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.

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“…Empirical estimates of total exchange across some sectors of shelf edge have been made on the basis of (i) changing properties of water flowing along the slope, (ii) variance in cross-slope flow, (iii) cross-slope dispersion of drifters. Thus along the Iberian slope, northward-flowing Mediterranean water has lateral diffusivity ∼500 m 2 /s (Daniault et al, 1994; basis i). Off western Galicia, cross-slope current variance (19 mm/s) 2 (basis ii) implies cross-slope exchange ∼3.8 m 2 /s in 200 m, or equivalent lateral diffusivity also ∼500 m 2 /s taking the offshore scale as the distance from the coast to the 200 m depth contour (26 km; Huthnance et al, 2002).…”

Section: Observationsmentioning

confidence: 99%

Deep ocean exchange with west-European shelf seas

2009

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Abstract. We review mechanisms and studies of exchange between the north-east Atlantic and the adjacent shelf seas. Well-developed summer upwelling and associated filaments off Portugal and north-west Spain give exchange O(3 m 2 /s per unit length of shelf). Prevailing westerly winds further north drive exchange O(1 m 2 /s). Poleward flow along most of the upper slope has associated secondary circulation O(1 m 2 /s), meanders and eddies. Eddies are shed from slope waters into the Bay of Biscay, and local exchanges occur at shelf spurs and depressions or canyons (e.g. dense-water cascading of order 1 m 2 /s). Tidal transports are larger, but their reversal every six hours makes exchange largely ineffective except where internal tides are large and non-linear, as in the Celtic Sea where solitons carry water with exchange O(1 m 2 /s). These various physical exchanges amount to an estimated 2-3 m 2 /s per unit length of shelf, between ocean and shelf. A numerical model estimate is comparable: 2.5×10 6 m 3 /s onto and off the shelf from Brittany to Norway. Mixing controls the seasonal thermocline, affecting primary production and hence fluxes and fate of organic matter. Specifically, CO 2 take-up by primary production, settling below the thermocline before respiration, and then off-shelf transport, make an effective shelf-sea "pump" (for CO 2 from the atmosphere to the deep ocean). However, knowledge of biogeochemical fluxes is generally sparse, giving scope for more measurements, model validation and estimates from models.

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Circulation and mixing of Mediterranean water west of the Iberian Peninsula

Cited by 91 publications

References 27 publications

Temperature–salinity distribution in the northeastern Atlantic from ship and Argo vertical casts

Temperature–salinity distribution in the northeastern Atlantic from ship and Argo vertical casts

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

Deep ocean exchange with west-European shelf seas

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