Spring and winter water mass composition in the Brazil-Malvinas Confluence

Maamaatuaiahutapu, Keitapu; Garçon, Véronique; Provost, Christine; Boulahdid, Mostefa; Bianchi, Alejandro A.

doi:10.1357/0022240943077064

Cited by 48 publications

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“…The analysis is performed on a seasonal basis to examine changes in water mass composition during the year. A similar seasonal water mass study for the western South Atlantic Ocean was conducted by Maamaatuaiahutapu et al (1994) and for the thermocline in the Indian Ocean by You (1997).…”

Section: Introductionmentioning

confidence: 90%

Seasonal Water Mass Analysis for the Straits of Juan de Fuca and Georgia

Masson

2006

Atmosphere-Ocean

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A quantitative analysis of water masses in the coastal waters of southern British Columbia is performed with the Optimum Multiparameter (OMP) analysis method that optimizes the use of a hydrographic dataset by solving an over-determined linear set of mixing equations. The method is applied to a seasonal dataset collected over five years in the Strait of Georgia, a large semi-enclosed coastal basin, as well as in Juan de Fuca Strait, its main connection to the Pacific Ocean. Abundant freshwater discharge into the coastal basin forces an estuarine exchange with oceanic shelf water. Six water characteristics of five source water types are used to obtain mixing proportions over the estuary for each of the four seasons. The model results are found to corroborate known aspects of the local dynamics such as the presence of a deep shelf inflow into Juan de Fuca Strait and of the Columbia River plume in winter at the mouth of the strait. The analysis also quantifies lesser known features of the region, such as the characteristics of the mid-depth intrusions within the Strait of Georgia and the marked effect of remineralization on nutrient distributions in the deep water of the coastal basin. RESUMÉ [Traduit par la rédaction] On effectue une analyse quantitative des masses d'eau dans la zone maritime littorale du sud de la Colombie-Britannique par la méthode de l'analyse multiparamétrique optimale (AMO) qui optimise l'utilisation d'un ensemble de données hydrographiques en résolvant un ensemble linéaire surdéterminé d'équations de mélange. La méthode est appliquée à un ensemble de données saisonnières recueillies sur une période de cinq ans dans le détroit de Georgie, un vaste bassin côtier semi-fermé, ainsi que dans le détroit de Juan de Fuca, son lien principal avec le Pacifique. L'arrivée d'une grande quantité d'eau douce dans le bassin côtier force un échange estuarien avec l'eau océanique de la plate-forme. On utilise six caractéristiques hydriques de cinq types d'eau sources pour obtenir les proportions de mélange dans l'estuaire pour chacune des quatre saisons. On trouve que les résultats du modèle s'accordent avec les caractéristiques connues de la dynamique locale, comme la présence d'un courant profond entrant dans le détroit de Juan de Fuca depuis la plate-forme et la présence du panache du fleuve Columbia en hiver à l'embouchure du détroit. L'analyse quantifie aussi des aspects moins connus de la région, comme les caractéristiques des intrusions à profondeur moyenne dans le détroit de Georgie et les effets prononcés de reminéralisation sur la distribution des nutriants dans les eaux profondes du bassin côtier. ATMOSPHERE-OCEAN 44 (1) 2006, 1-15

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Section: Introductionmentioning

confidence: 90%

Seasonal Water Mass Analysis for the Straits of Juan de Fuca and Georgia

Masson

2006

Atmosphere-Ocean

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“…1, Gordon 1981;1989). The location of this zone shifts seasonally reaching higher latitudes during austral summer (i.e., December 21st to March 21st, Maamaatuaiahutapu et al 1994;Barré et al 2006). Shallow coastal waters near the borders of Uruguay and Argentina (i.e., depths < 50 m) are highly influenced by the Río de la Plata freshwater discharge that exhibits monthly variations, with higher discharges during the austral fall-winter and the lowest discharge during the austral spring-summer (Sepúlveda et al 2004).…”

Section: Study Areamentioning

confidence: 99%

Tamoya haplonema (Cnidaria: Cubozoa) from Uruguayan and adjacent waters: oceanographic context of new and historical findings

Leoni

González

Ortega³

et al. 2016

Mar Biodivers Rec

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New records of the cubozoan jellyfish Tamoya haplonema in Uruguayan waters are reported together with historical records for the region, and associated with the oceanographic conditions at the moment of the finding. Occurrences of the species are mainly associated with positive Sea Surface Temperature Anomalies especially during summer months when the intrusion of warm oceanic waters to the Uruguayan coastline is stronger. This was particularly strong during 2012-2013, when a dry period enhanced this scenario. This species is the only cubozoan present in Uruguay, with a sporadic occurrence and so far has no appreciated negative effects on public health. However, from observed increasing frequency of positive temperature anomalies it would be reasonable to predict a future southward shift in the latitudinal distribution of T. haplonema. In this context, occurrence of this toxic species along Uruguayan coastal waters must be considered with particular attention to the potential negative impact on tourism and on general public health.

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“…Most likely, the frontal system is more stable in position at depth than near the sea surface due to the reduced influence of the seasonal atmospheric signal. Within the Confluence Zone it is believed that mixing occurs between newly ventilated, fresh AAIW that is advected along the outer edges of the retroflecting Falkland Current and the older AAIW that is advected southward within the western branch of the subtropical gyre underneath the Brazil Current (Maamaatuaiahutapu et al, 1993).…”

Section: Cross Frontal Mixing At the Confluence Zonementioning

confidence: 99%

Kinematic elements of Antarctic Intermediate Water in the western South Atlantic

Boebel

Schmid

Zenk

1999

Deep Sea Research Part II: Topical Studies in Oceanography

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The northward flowing Antarctic Intermediate Water (AAIW) is a major contributor to the large-scale meridional circulation of water masses in the Atlantic. Together with bottom and thermocline water, AAIW replaces North Atlantic Deep Water that penetrates into the South Atlantic from the North. On the northbound propagation of AAIW from its formation area in the south-western region of the Argentine Basin, the AAIW progresses through a complex spreading pattern at the base of the main thermocline. This paper presents trajectories of 75 subsurface floats, seeded at AAIW depth. The floats were acoustically tracked, covering a period from December 1992 to October 1996. Discussions of selected trajectories focus on mesoscale kinematic elements that contribute to the spreading of AAIW. In the equatorial region, intermittent westward and eastward currents were observed, suggesting a seasonal cycle of the AAIW flow direction. At tropical latitudes, just offshore the intermediate western boundary current, the southward advection of an anticyclonic eddy was observed between 5°S and 11°S. Farther offshore, the flow lacks an advective pattern and is governed by eddy diffusion. The westward subtropical gyre return current at about 28°S shows considerable stability, with the mean kinetic energy to eddy kinetic energy ratio being around one. Farther south, the eastward deeper South Atlantic Current is dominated by large-scale meanders with particle velocities in excess of 60 cm s\ . At the Brazil-Falkland Current Confluence Zone, a cyclonic eddy near 40°S 50°W seems to act as injector of freshly mixed AAIW into the subtropical gyre. In general, much of the mixing of the various blends of AAIW is due to the activity of mesoscale eddies, which frequently reoccupy similar positions.

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Spring and winter water mass composition in the Brazil-Malvinas Confluence

Cited by 48 publications

References 0 publications

Seasonal Water Mass Analysis for the Straits of Juan de Fuca and Georgia

Seasonal Water Mass Analysis for the Straits of Juan de Fuca and Georgia

Tamoya haplonema (Cnidaria: Cubozoa) from Uruguayan and adjacent waters: oceanographic context of new and historical findings

Kinematic elements of Antarctic Intermediate Water in the western South Atlantic

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