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Registros recuperados: 22
Primeira ... 12 ... Última
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A hydrographic section from South Africa to the southern limit of the Antarctic Circumpolar Current at the Greenwich meridian ArchiMer
Gladyshev, S; Arhan, Michel; Sokov, A; Speich, Sabrina.
The properties and circulation of water masses leaving and entering the Atlantic Ocean south of Africa are examined using data from a hydrographic and Lowered acoustic Doppler current profiler section from South Africa to the southern limit of the Antarctic Circumpolar Current (ACC). At the upper levels, the ACC fronts are well determined using either classical water mass definitions or gradient-based criteria. While the locations of the Subantarctic Front (SAF), Polar Front (PF), and Southern ACC Front (SACCF) seem controlled by the neighbouring ridges, that of the Subtropical Front (STF) is much influenced in this region (similar to 10 degrees E) by northwestward propagating Agulhas rings. No large amount of Subantarctic Mode Water (SAMW) is observed,...
Tipo: Text Palavras-chave: Water masses; Fronts; Bottom circulation; Transport; Agulhas eddies; Antarctic Circumpolar Current.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-6097.pdf
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An altimetry-based gravest empirical mode south of Africa: 2. Dynamic nature of the Antarctic Circumpolar Current fronts ArchiMer
Swart, Sebastiaan; Speich, Sabrina.
Swart et al. (2010) applied altimetry data to the gravest empirical mode south of Africa to yield a 16 year time series of temperature and salinity sections. In this study we use these thermohaline sections to derive weekly estimates of heat content (HC) and salt content (SC) at the GoodHope meridional transect of the Antarctic Circumpolar Current (ACC). These estimates compare favorably to observed data. The resulting 16 year time series of HC and SC estimates are used to explain the subsurface thermohaline variability at each ACC front and frontal zone. The variability at the Subantarctic Zone (SAZ) is principally driven by the presence of Agulhas Rings, which occur in this region approximately 2.7 times per annum and are responsible for the longest and...
Tipo: Text Palavras-chave: Altimetry; ACC; Fronts.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00002/11307/7892.pdf
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Ausbreitung und Vermischung des Zentralwassermassen in den Tropengebieten der Ozeane.1 : Atlantischer Ozean ArchiMer
Tomczak, M.
Tipo: Text Palavras-chave: Central Water; Mixing; Fronts; Tropical ocean.
Ano: 1984 URL: http://archimer.ifremer.fr/doc/00323/43411/43090.pdf
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Biología reproductiva comparada de especies de la familia Sciaenidae en aguas del Río de la Plata y Costa Bonaerense OceanDocs
Militelli, M.I..
In the Argentine Sea (SW Atlantic), particularly in the Bonaerense Coastal Zone there are two frontal zones, the waterfront area of the Rio de la Plata and the southern area of the province called El Rincón. The fauna of the Bonaerense Coastal Area has its own characteristics and in the case of fish is defined by dominant species, as is the whole of Sciaenidae family composed of seven species: white mouth croaker (Micropogonias furnieri), striped weakfish (Cynoscion guatucupa), king weakfish (Macrodon ancylodon), black drum (Pogonias cromis), Argentine croaker (Umbrina canosai), drum (Paralonchurus brasiliensis) and southern kingfish (Menticirrhus americanus). In the present work is discussed in a comparative way various aspects of the reproductive cycle...
Tipo: Theses and Dissertations Palavras-chave: Brackishwater fish; Reproduction; Spawning grounds; Coastal waters; Fronts; Environmental conditions; Histology; Reproduction; Spawning grounds; Coastal waters; Environmental conditions; Http://aims.fao.org/aos/agrovoc/c_6507; Http://aims.fao.org/aos/agrovoc/c_7277; Http://aims.fao.org/aos/agrovoc/c_25205; Http://aims.fao.org/aos/agrovoc/c_32980.
Ano: 2007 URL: http://hdl.handle.net/1834/3549
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Biomasa y distribución espacial del bacterioplancton en el sector norte de la plataforma continental argentina (34º S-41º S) OceanDocs
Hozbor, M.C.; Hernández, D.R.; Cucchi Colleoni, A.D.; Costagliola, M.C.; Peressutti, S.R..
The northern sector of the Argentine continental shelf (34º S-41º S) is a highly productive area that sustains important fishery resources like Argentine anchovy (Engraulis anchoita) and is characterized by the presence of frontal zones with retention of detritus and plankton. In marine environments the bacterioplankton represents one of the main components of the trophic nets and plays a key role in biogeochemical cycles. In this ecosystem biomass and bacterioplankton distribution as well as their relation to environmental variables were analyzed. The highest chlorophyll a values, not significantly related to bacterioplankton (p > 0.05), were found in frontal and coastal areas. Abundance, bacterial biomass and cell volume values ranged 0.48-5.42 x 106...
Tipo: Journal Contribution Palavras-chave: Picoplankton; Bacteria; Biomass; Fronts; Coastal zone; Abundance; Environmental factors; Geographical distribution.
Ano: 2013 URL: http://hdl.handle.net/1834/5498
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Climatología de los frentes de marea en la Plataforma Continental y su rol en los flujos mar-atmósfera de CO2 OceanDocs
Bianucci, L..
En este trabajo se caracterizaron los frentes de marea en la Plataforma Continental Argentina al sur de 40°S y los flujos de CO2 entre el mar y la atmósfera en la región, analizándose su relación con dichos frentes. Los frentes de marea separan aguas costeras cuasi-homogéneas de aguas estratificadas de la plataforma media. La zona costera se homogeneiza por la mezcla vertical producida por fricción de las energéticas corrientes de marea que se dan en la región. La plataforma media se encuentra estratificada en verano debido al calentamiento superficial del mar, presentando una termoclina estacional bien desarrollada. La mezcla vertical a cada lado de los frentes y los movimientos verticales en la zona frontal afectan a la producción primaria y a los flujos...
Tipo: Theses and Dissertations Palavras-chave: Fronts; Atmospheric fronts; Continental shelves; Air-sea interaction; Climatology; Tidal flow; Seasonal distribution; Climatology; Continental shelves.
Ano: 2004 URL: http://hdl.handle.net/1834/3856
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Determining bluefin tuna habitat through frontal features in the Mediterranean sea ArchiMer
Royer, Francois; Fromentin, Jean-marc; Farrugio, Henri; Gaspar, Philippe.
The distribution patterns of bluefin tuna schools observed during the STROMBOLI EU project (2000-2002) were analysed in relation to oceanographic conditions. High-resolution radiometers (AVHRR and SeaWiFS) were used on a daily basis to derive maps of environmental variability. An edge detection technique was especially applied to estimate the position of frontal features. Using a variety of geostatistical and point process techniques, we were able to show that the distribution of bluefin schools was partially driven by the occurrence of transient fronts in the Gulf of Lions. This is believed to be mainly a trophic association, since enhanced convergence and retention processes occur at fronts, possibly leading to higher prey densities (e.g. anchovies). The...
Tipo: Text Palavras-chave: Thunnus thynnus; Aerial survey; Gulf of Lions; Sea surface temperature; Ocean colour; Fronts.
Ano: 2005 URL: http://archimer.ifremer.fr/doc/00194/30504/28914.pdf
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Effects of the submesoscale on the potential vorticity budget of ocean mode waters ArchiMer
Wenegrat, Jacob O.; Thomas, Leif N.; Gula, Jonathan; Mcwilliams, James C..
Non-conservative processes change the potential vorticity (PV) of the upper ocean, and later, through the subduction of surface waters into the interior, affect the general ocean circulation. Here we focus on how boundary layer turbulence, in the presence of submesoscale horizontal buoyancy gradients, generates a source of potential vorticity at the ocean surface through a balance known as the Turbulent ThermalWind. This source of PV injection at the submesoscale can be of similar magnitude to PV fluxes from the wind and surface buoyancy fluxes, and hence can lead to a net injection of PV onto outcropped isopycnals even during periods of surface buoyancy loss. The significance of these dynamics is illustrated using a high-resolution realistic model of the...
Tipo: Text Palavras-chave: Ageostrophic circulations; Atmosphere-ocean interaction; Fronts; Ocean dynamics; Potential vorticity; Boundary layer.
Ano: 2018 URL: http://archimer.ifremer.fr/doc/00452/56347/57937.pdf
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El zooplancton del hábitat reproductivo de la población bonaerense de anchoíta (Engraulis anchoita), con especial énfasis en crustáceos OceanDocs
Viñas, M.D.; Marrari, M.; Di Mauro, R.; Cepeda, G.D.; Padovani, L.N..
The information gathered in Argentine anchovy (Engraulis anchoita) Northern population assessment cruises allowed to perform studies on the zooplankton community of the Buenos Aires shelf since 1995. In this work the most relevant results as regards the taxonomy and size structure of the community, faunistic areas, and 'key' species in relation to the hydrographic conditions and frontal systems of the region are presented. Besides, the consequences those results might have on Argentine anchovy trophic ecology are analyzed. The taxonomic groups studied included copepods, cladocerans, appendicularians, chaetognaths, amphipods, and euphausiids. The multivariate analysis applied to quantitative data allowed to clearly distinguish three faunistic areas with...
Tipo: Journal Contribution Palavras-chave: Zooplankton; Biogeography; Fauna; Fronts; Trophic relationships; Abundance; Pelagic fisheries.
Ano: 2013 URL: http://hdl.handle.net/1834/5497
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Factores oceanográficos relacionados con la abundancia relativa de anchoíta (Engraulis anchoita) sobre la plataforma bonaerense (34°S-41°S) durante la primavera OceanDocs
Martos, P.; Hansen, J.E.; Negri, R.M.; Madirolas, A..
Research has been conducted to study the relationship between some physical variables and the relative abundance of the northern stock of the Argentine anchovy (Engraulis anchoita) within the main area of distribution of the stock during springtime. Basic data were recorded during four research surveys mainly aimed at the acoustic assessment of the stock between 34°S and 41° 30'S (Buenos Aires prov., Argentina - Uruguay). The cruises were always carried out in October from 1993 to 1996. Several environmental variables were simultaneously input into a General Linear Model to analyze the variations on fish abundance; however, the model did not account for more than 17-20% of the total variance. Nevertheless most of those factors (sea surface temperature,...
Tipo: Journal Contribution Palavras-chave: Clupeoid fisheries; Seasonal distribution; Abundance; Stocks; Fronts; Salinity gradients; Stocks; Http://aims.fao.org/aos/agrovoc/c_28772.
Ano: 2005 URL: http://hdl.handle.net/1834/1559
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Habitat use, vertical and horizontal behaviour of Atlantic bluefin tuna ( Thunnus thynnus ) in the Northwestern Mediterranean Sea in relation to oceanographic conditions ArchiMer
Bauer, Robert Klaus; Fromentin, Jean-marc; Demarcq, Herve; Bonhommeau, Sylvain.
We investigated the habitat utilization, vertical and horizontal behaviour of Atlantic bluefin tuna Thunnus thynnus (ABFT) in relation to oceanographic conditions in the northwestern Mediterranean Sea, based on 36 pop-up archival tags and different environmental data sets. Tags were deployed on early mature ABFT (127–255 cm) between July and November in 2007-2014, on the shelf area off Marseille, France. The data obtained from these tags provided 1643 daily summaries of ABFT vertical behaviour over 8 years of tag deployment. Based on a hierarchical clustering of this data, we could identify four principle daily vertical behaviour types, representing surface (≦10m) and subsurface (10–100 m) orientation, moderate (50–200 m) and deep (≧200m) diving behaviour....
Tipo: Text Palavras-chave: Thunnus thynnus; Habitat use; Spike dives; Fronts; Thermal stratification; Archival tags.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00382/49329/49709.pdf
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Indicadores del estado del ambiente marino patagónico en áreas frontales OceanDocs
Carranza, M..
En este trabajo se caracterizan las regiones frontales altamente productivas del Mar Patagónico empleando datos de clorofila satelital (CSAT) derivada del Sea-viewing Wide Field-of-view Sensor (SeaWiFS) durante el período 1998-2006. A partir de estos datos se identifican cuatro áreas de máxima concentración de clorofila: el Frente del Talud, el Frente de la Plataforma Media, el Frente de Patagonia Austral y el Frente de Valdés. Los tres primeros se definen por regiones de amplitud media de CSAT > 3.5 mg/m3, mientras que el último se define por la región de CSAT media de verano > 2 mg/m3. Sobre estas regiones se elaboran indicadores de clorofila (CSAT), temperatura superficial del mar (SST) y viento en superficie. La temperatura es derivada del...
Tipo: Theses and Dissertations Palavras-chave: Fronts; Shelf edge fronts; Surface temperature; Temporal variations; Remote sensing; Water colour; Chlorophylls; Winds; Winds; Remote sensing; Chlorophylls; Http://aims.fao.org/aos/agrovoc/c_8401; Http://aims.fao.org/aos/agrovoc/c_6498; Http://aims.fao.org/aos/agrovoc/c_1577.
Ano: 2009 URL: http://hdl.handle.net/1834/3857
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La dynamique à sousmésoéchelle sur le plateau continental du Golfe de Gascogne ArchiMer
Yelerci, Ozge.
This thesis explores the submesoscale dynamics in the Bay of Biscay continental shelf. In the first part, submesoscale features over the shelf are identified using remotely sensed high resolution sea surface temperature (SST) images by MODIS. Front detection is achieved through singularity exponents, a novel method of calculating irregularities on the SST fields, and an index for the frontal activity is generated. Results are complemented with 2.5 km horizontal resolution numerical simulations. Three main types of fronts are presented: i) tidal mixing fronts along the coast and most significantly in the Ushant region; ii) shelf break front related to internal tidal wave activity; iii) fresh water fronts along the edge of the river plumes in winter. In the...
Tipo: Text Palavras-chave: Dynamique à sousmésoéchelle; Modèle numérique océanique a haute résolution; Golfe de gascogne; Exposants de singularité; Données satellites de température de surface de la mer; Submesoscale dynamics; Fronts; Bay of Biscay.
Ano: 2017 URL: https://archimer.ifremer.fr/doc/00497/60910/64259.pdf
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Mesoscale and Sub-Mesoscale structures observed during High resolution surveys in Western Mediterranean Basin ArchiMer
Garreau, Pierre; Dumas, Franck; Louazel, Stephanie; Correard, Stephanie.
The Mediterranean Sea is often referred as a “pocket ocean” exhibiting many processes that are primary interest the global ocean circulation given the opportunity to investigate a large panel of oceanic features in a relatively restrained area. Recent field experiments based on the multi-plateform integrated monitoring MOOSE or on intensive targeted experiment HYMEX revisited the hydrology and the dynamics of the Western Basin. Such approaches emphasized the ubiquity of the fine scale dynamics in the Mediterranean dynamics. An overview of the observed processes during 5 recent fields experiments are  presented and discussed regarding meso- and submeso-scale processes.
Tipo: Text Palavras-chave: Mesoscale phenomena; Western Mediterranean; Fronts.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00582/69398/67247.pdf
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Modelado numérico del ecosistema de los golfos norpatagónicos OceanDocs
Tonini, M.H..
This dissertation analyses the oceanic circulation of the Norpatagonian Gulfs, a region of the Argentinean Sea that has long been recognized for the high productivity and biodiversity of the ecosystem. The study aims towards a systematic exploration of the physical processes that control the circulation using a high resolution three dimensional numerical model. To facilitate the dynamical understanding of the results our experimental strategy was to start with a constant density (barotropic) model forced by tides and winds, and to progress to a more complex case including density stratification generated by surface fluxes of heat and humidity. The main result that stems from the numerical experiments is that tidal forcing significantly contributes to the...
Tipo: Theses and Dissertations Palavras-chave: Water masses; Oceanography; Currents (water); Fronts; Ocean circulation; Mathematical models; Tides; Winds; Physical oceanography; Tides; Winds; Physical oceanography; Oceanography; Mathematical models.
Ano: 2010 URL: http://hdl.handle.net/1834/3877
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Observation on the bacteriology of fronts : some problems of methodology ArchiMer
Floodgate, G.d.; Lochte, K.; Egan, B..
The data obtained in surveys to investigate the bacteriological aspects of the biology of two contrasting frontal systems has shown that the Inherent homeostasis and the complexity of the environment, together with the Imprecision of the data, lead to biomass values that are difficult to interpret in terms of the physical factors governing the formation of fronts. Although biochemical measurements offer some promise of providing more reliable and less confusing information, the oeed to develop high precision methods that can be made very frequently is emphasised.
Tipo: Text Palavras-chave: Bacteria; Discontinuities; Fronts; Methodology.
Ano: 1982 URL: http://archimer.ifremer.fr/doc/00306/41742/40953.pdf
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Observed atlantification of the Barents Sea causes the Polar Front to limit the expansion of winter sea ice ArchiMer
Barton, Benjamin I.; Lenn, Yueng-djern; Lique, Camille.
Barents Sea Water (BSW) is formed from Atlantic Water that is cooled through atmospheric heat loss and freshened through seasonal sea ice melt. In the eastern Barents Sea, the BSW and fresher, colder Arctic Water meet at the surface along the Polar Front (PF). Despite its importance in setting the northern limit of BSW ventilation, the PF has been poorly-documented, mostly eluding detection by observational surveys that avoid seasonal sea ice. In this study, satellite sea surface temperature (SST) observations are used in addition to a temperature and salinity climatology to examine the location and structure of the PF, and characterise its variability over the period 1985 – 2016. It is shown that the PF is independent of the position of the sea ice edge...
Tipo: Text Palavras-chave: Arctic; Sea ice; Fronts; Sea surface temperature; Satellite observations.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00448/56003/57509.pdf
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On the Movements of the North Atlantic Subpolar Front in the Preinstrumental Past* ArchiMer
Marchal, Olivier; Waelbroeck, Claire; Colin De Verdiere, Alain.
Three sediment records of sea surface temperature (SST) are analyzed that originate from distant locations in the North Atlantic, have centennial-to-multicentennial resolution, are based on the same reconstruction method and chronological assumptions, and span the past 15 000 yr. Using recursive least squares techniques, an estimate of the time-dependent North Atlantic SST field over the last 15 kyr is sought that is consistent with both the SST records and a surface ocean circulation model, given estimates of their respective error (co)variances. Under the authors' assumptions about data and model errors, it is found that the 10 degrees C mixed layer isotherm, which approximately traces the modern Subpolar Front, would have moved by ~15 degrees of...
Tipo: Text Palavras-chave: Inverse methods; Kalman filters; Climate variability; Circulation/ Dynamics; Geographic location/entity; Oceanic variability; Variability; Mathematical and statistical techniques; Fronts; North Atlantic Ocean.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00318/42922/42423.pdf
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Reproducción de la corvina rubia Micropogonias furnieri del sector rioplatense. Su relación con los gradientes horizontales de salinidad. OceanDocs
Macchi, G.J..
Reproduction of white croaker collected during 1991-1993 in the Argentine-Uruguayan Common Fishing Zone (CFZ)(34°-39°30'S), was studied by means of histological analysis of ovaries. Areal and seasonal maturity stage distributions were compared; ripeness degree was correlated to horizontal salinity gradients. During June and July an overall predominance of the resting stage was observed; nevertheless, a high proportion of females in early maturation was detected near Cabo San Antonio and Punta Piedras. In late October-early November an increase of maturing individuals was observed. Females in advanced maturity stage and partially spent,with postovulatory follicles, were collected mainly in estuarine waters with wide bottom salinity ranges (between 9-25...
Tipo: Journal Contribution Palavras-chave: Ovaries; Salinity effects; Estuarine front; Reproduction; Salinity gradients; Sexual maturity; Fronts; Ovaries; Reproduction; Sexual maturity; Http://aims.fao.org/aos/agrovoc/c_5456; Http://aims.fao.org/aos/agrovoc/c_6507; Http://aims.fao.org/aos/agrovoc/c_7016.
Ano: 1997 URL: http://hdl.handle.net/1834/1932
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Spatial and Seasonal Distributions of Frontal Activity over the French Continental Shelf in the Bay of Biscay ArchiMer
Yelekci, Ozge; Charria, Guillaume; Capet, Xavier; Reverdin, Gilles; Sudre, Joel; Yahia, Hussein.
The frontal activity in coastal regions remains a research field where a large number of open questions needs to be addressed to quantify the potential impact of these processes on dependent systems (e.g. biogeochemical activity). Spatial and seasonal distributions of Sea Surface Temperature (SST) fronts (∼1-100 km) in the vicinity of main French rivers, Gironde and Loire, are explored over the continental shelf North of 45 °N in the Bay of Biscay. A high resolution (1 km spatial and daily temporal resolutions) dataset of 11 years' (2003 to 2013) remotely sensed SST by MODIS sensor onboard Aqua and Terra satellites has been investigated and compared with coastal numerical model experiments. The detection and characterization fronts with fluctuating...
Tipo: Text Palavras-chave: Bay of Biscay; Fronts; Submesoscale; Satellite; Sea surface temperature; Singularity exponent.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00389/50013/50602.pdf
Registros recuperados: 22
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