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  • 1
    Publication Date: 2021-05-19
    Description: The Cape Verde Front (CVF) separates the North Atlantic subtropical gyre (NASG) from the north-eastern North Atlantic tropical gyre (NATG). Within the NASG, the Canary Current (CC) and the Canary Upwelling Current (CUC) comprise a relatively shallow (down to about 200-300 m) flow of North Atlantic Central Waters (NACW): the CC is found far offshore as a wide and poorly defined current while the CUC is a near-slope intense baroclinic jet linked to the coastal upwelling front. Within the top 300 m of the NATG, the along-slope Mauritania Current and the Cape Verde Current (CVC, a north-eastern extension of the North Equatorial Counter Current that broadly rotates around the Guinea Dome) carry South Atlantic Central Waters northwards. As a result, the frontal system is the site of intense along-slope flow convergence and offshore transport in the top 300 m of the water column. Further deep, down to some 500 m, the interior flow is very weak in both gyres, likely dominated by mesoscale features, except along the continental slope, where the northward Poleward Undercurrent (PUC) feeds through localized inputs from the interior ocean; in particular, within the NATG the CVC appears as responsible for southward transfer of NACW, across the CVF, which eventually reaches the PUC.
    Description: Published
    Keywords: Eastern boundary currents ; Cape Verde Front ; Canary Upwelling Current ; Poleward Undercurrent ; Guinea Dome ; CCLME
    Repository Name: AquaDocs
    Type: Report Section , Refereed
    Format: pp. 81-92
    Location Call Number Limitation Availability
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  • 2
    Publication Date: 2021-05-19
    Description: Inorganic nutrients increase with depth as a result of the enhanced remineralization of organic matter with aging waters (the time since they were last near the sea surface), and the opposite happens with dissolved oxygen (except within the saturated surface mixed layer). In the Canary Current Large Marine Ecosystem there is also a marked latitudinal gradient, with the Cape Verde Front separating relatively nutrient-poor and oxygen-rich subtropical waters from the nutrient-rich and oxygen-poor tropical waters. Along a latitudinal band off North-West Africa, coastal upwelling brings the subsurface waters towards the sea surface, locally raising the inorganic nutrient levels. This becomes an important lateral source to both gyres, especially to the nutrient-poor subtropical one, taking place through lateral mixing (mainly as a result of the instability of the coastal-upwelling baroclinic jet) and localized coastal filaments (in those regions, typically capes, where the coastal flow converges and offshore advection takes place). In the southernmost portion of our domain, within tropical waters, there is also high (wind-induced) offshore primary production. This, together with the slow ventilation of the subsurface waters, leads to much enhanced remineralization, producing a region with very low oxygen and high inorganic nutrient levels, the oxygen minimum zone of the North Atlantic Ocean.
    Description: Published
    Keywords: Cape Verde Front ; Inorganic nutrient supply ; Biogeochemical processes ; Spatial distributions ; Oxygen minimum zone ; CCLME
    Repository Name: AquaDocs
    Type: Report Section , Refereed
    Format: pp. 133-142
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  • 3
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    IOC-UNESCO | Paris, France
    Publication Date: 2021-05-19
    Description: North of Cape Blanc, the north-easterly winds cause offshore flow of surface waters that are replaced by subsurface inflow of relatively cold and nutrient-rich waters, driving the vertical cell of coastal upwelling. This vertical circulation, together with surface heating and horizontal mixing, causes the coastal upwelling front (typically about 200 m deep) that separates cold onshore from warm offshore waters. A southward baroclinic coastal jet is associated to this front, which causes vertical shear and mixing that contribute to the intensity of the vertical cell. Very importantly, this jet feeds from upstream waters, resulting in an along-slope coherent flow, or the horizontal cell of coastal upwelling – this is the Canary Upwelling Current (CUC) that connects all surface coastal African waters north of Cape Blanc. Further south, because of the northward offshore flow and the seasonality of the winds, the connection remains only during winter and spring, very close to shelf break and in the top 100 m. North of Cape Blanc, a Poleward Undercurrent (PUC) flows in the relatively homogenous upwelled waters that found over the continental slope. South of Cape Blanc the PUC appears as a nearshore expression of the Mauritania Current. Both the southward CUC and the northward PUC constitute the true skeleton of the Canary Current Large Marine Ecosystem.
    Description: Published
    Keywords: Coastal upwelling ; Recirculation cells ; Canary Upwelling Current ; Poleward Undercurrent ; CCLME ; ASFA15::E::Ekman transport
    Repository Name: AquaDocs
    Type: Report Section , Refereed
    Format: pp. 93-103
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  • 4
    Publication Date: 2021-11-20
    Description: Conocer los patrones de circulación costera es fundamental para gestionar adecuadamente la franja litoral, especialmente en áreas con alta presión antrópica. Con el objetivo de determinar las características de las corrientes costeras en el golfo de Urabá, se midieron y analizaron los patrones estacionales de circulación superficial durante las épocas de mucha y poca lluvia a lo largo de 6 km de costa, entre las espigas litorales de punta de Las Vacas y punta Yarumal del municipio de Turbo, Antioquia. Estas mediciones se realizaron con derivadores superficiales, que fueron lanzados en diversos estadios de la marea y rastreados durante periodos cercanos al ciclo semidiurno. Las mediciones in situ se analizaron considerando la evolución de la marea y los vientos observados en una estación climática ubicada cerca del golfo. Los patrones de circulación mostraron un comportamiento diferente durante las dos estaciones del año. La temporada de mucha lluvia, con vientos del sur, presentó trayectorias hacia el norte y la temporada de poca lluvia, con vientos del norte, las trayectorias fueron hacia el sur. Aunque los patrones de circulación mostraron una fuerte relación con la marea y el viento, las trayectorias de algunos derivadores se modificaron localmente por la presencia de geoformas como las bahías de Turbo y El Uno.
    Description: Good knowledge of the coastal circulation patterns is essential for a proper management of the coastline, especially in areas with a high anthropic pressure. In order to determine the main characteristics of the coastal currents in the Gulf of Urabá, the seasonal patterns of surface circulation were measured and analyzed during times of high and low rainfall along 6 km of coastline, between the Punta de Las Vacas and Punta Yarumal coastal spit systems, in the municipality of Turbo, Antioquia. These measurements were made with surface drifters, which were launched at different tide stages and tracked for time periods based on the semi-diurnal cycle. The in-situmeasurements were analyzed alongside tide and wind data from a climatic station located near the gulf. The circulation patterns behaved differently depending on the season of the year. In the rainy season, with southerly winds, the drifters moved mainly towards the north while during the dry season, with northerly winds, all the drifters moved to the south. Although the circulation patterns showed a strong relationship with the tidal cycle and wind conditions, the Turbo and El Uno Bays modified some of the drifter’s paths.
    Description: Published
    Description: Refereed
    Keywords: tide ; circulación superficial ; viento ; marea ; derivadores ; corrientes costeras ; ASFA_2015::S::Surfaces ; ASFA_2015::C::Circulation ; ASFA_2015::W::Wind ; ASFA_2015::D::Drifters ; ASFA_2015::C::Coastal currents
    Repository Name: AquaDocs
    Type: Journal Contribution
    Format: pp. 9-30
    Location Call Number Limitation Availability
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