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Registros recuperados: 24 | |
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Treguier, Anne-marie; Gourcuff, Claire; Lherminier, Pascale; Mercier, Herle; Barnier, Bernard; Madec, Gurvan; Molines, Jean-marc; Penduff, Thierry; Czeschel, Lars; Boning, Claus. |
Numerical models are used to estimate the meridional overturning and transports along the paths of two hydrographic cruises, carried out in 1997 and 2002 from Greenland to Portugal. We have examined the influence of the different paths of the two cruises and found that it could explain 0.4 to 2 Sv of difference in overturning (the precise value is model-dependent). Models show a decrease in the overturning circulation between 1997 and 2002, with different amplitudes. The CLIPPER ATL6 model reproduces well the observed weakening of the overturning in density coordinates between the cruises; in the model, the change is due to the combination of interannual and high-frequency forcing and internal variability associated with eddies and meanders. Examination of... |
Tipo: Text |
Palavras-chave: Ocean model; Thermohaline circulation; North Atlantic; Climate variability; Oceanography. |
Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2199.pdf |
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Frigola, J.; Moreno, A.; Cacho, I.; Canals, M.; Sierro, F. J.; Flores, J. A.; Grimalt, J. O.; Hodell, D. A.; Curtis, J. H.. |
The detailed analysis of the International Marine Past Global Changes Study core MD99-2343 recovered from a sediment drift at 2391 m water depth north of the island of Minorca illustrates the effects of climate variability on thermohaline circulation in the western Mediterranean during the last 12 kyr. Geochemical ratios associated with terrigenous input resulted in the identification of four phases representing different climatic and deepwater overturning conditions in the Western Mediterranean Basin during the Holocene. Superimposed on the general trend, eight centennial- to millennial-scale abrupt events appear consistently in both grain size and geochemical records, which supports the occurrence of episodes of deepwater overturning reinforcement in the... |
Tipo: Text |
Palavras-chave: Holocene climate variability; Thermohaline circulation; Western Mediterranean Sea. |
Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00233/34448/32900.pdf |
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Crosta, X.; Debret, M.; Denis, D.; Courty, M. A.; Ther, O.. |
Diatom data from a marine sediment core give insight on Holocene changes in sea- surface conditions and climate at high southern latitudes off Adelie Land, East Antarctica. The early to mid- Holocene was warmer than the late Holocene with a transition at similar to 4000 calendar years B. P. Sea ice was less present and spring- summer growing season was greater during the warm period relative to the cold one, thus limiting sea ice diatom production and favoring more open ocean diatom to develop. The long- term Holocene climatic evolution in East Antarctica is explained by a combination of a delayed response to local seasonal insolation changes coupled to the long memory of the Southern Ocean. Abrupt variations of the diatom relative abundances, indicating... |
Tipo: Text |
Palavras-chave: Antarctica; Sea ice; Holocene; Insolation; Thermohaline circulation. |
Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34642/33044.pdf |
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Rixen, Michel; Beckers, J; Levitus, S; Antonov, J; Boyer, T; Maillard, Catherine; Fichaut, Michele; Balopoulos, E; Iona, S; Dooley, H; Garcia, M; Manca, B; Giorgetti, A; Manzella, G; Mikhailov, N; Pinardi, N; Zavatarelli, M. |
Reconstructions of Mediterranean ocean temperature fields back to 1950 show a proxy relationship between heat content changes in the North Atlantic and the Western Mediterranean Deep Water ( WMDW) formed in the Gulf of Lions in winter, because of consistent air-sea heat fluxes over these areas, strongly correlated to the North Atlantic Oscillation ( NAO). |
Tipo: Text |
Palavras-chave: North Atlantic; West mediterranee; Thermohaline circulation; Temperature variation; Deep water; Water masses; Air sea heat flux. |
Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-760.pdf |
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Toucanne, Samuel; Jouet, Gwenael; Ducassou, Emmanuelle; Bassetti, Maria-angela; Dennielou, Bernard; Minto'O, Charlie Morelle Angue; Lahmi, Marjolaine; Touyet, Nicolas; Charlier, Karine; Lericolais, Gilles; Mulder, Thierry. |
Sortable silt particle-size data and stable isotope analyses from the Corsica Trough, western Mediterranean Sea, provide a continuous palaeoceanographic record of the inflow, ventilation and vertical fluctuations of the Levantine Intermediate Water (LIW) in the northern Tyrrhenian Sea for the last 130,000 years. The results presented herein reveal that climate changes drive the Mediterranean intermediate circulation on Milankovitch to millennial time-scales. Intensified intermediate inflow and ventilation in the Corsica Trough occurred throughout the last glacial interval, with a cold / faster – warm / slower pattern existing between the Dansgaard-Oeschger climatic oscillations (including Heinrich events) and the LIW variability. By contrast, a weak... |
Tipo: Text |
Palavras-chave: Levantine Intermediate Water; Mediterranean Sea; Thermohaline circulation; Palaeoceanography. |
Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00054/16506/14023.pdf |
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Blanke, Bruno; Arhan, Michel; Speich, Sabrina. |
Lagrangian analyses of a global ocean circulation model quantify the salinity changes experienced by the warm limb of the thermohaline circulation during the northward flow to the Atlantic deep convection regions. 6 Sv out of the estimated 10-Sv transfer from 45 degrees S to 47 degrees N flow through regions of prevailing surface evaporation: the southern and northern formation regions of Salinity Maximum Water and the Gulf of Cadiz/Mediterranean Sea domain. The remaining transport gains salinity through mixing with adjacent waters. As much as 6 Sv flow through the low-salinity surface mixed layer at the latitudes of the ITCZ whose effect annihilates that of the southern region of Salinity Maximum Water. Most of the salinity increase corresponds to the... |
Tipo: Text |
Palavras-chave: Salinity; Atlantic deep convection zones; Upper limb; Thermohaline circulation; Ocean circulation model. |
Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1213.pdf |
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Sierro, Fj; Hodell, Da; Curtis, Jh; Flores, Ja; Reguera, I; Colmenero-hidalgo, E; Barcena, Ma; Grimalt, Jo; Cacho, I; Frigola, J; Canals, M. |
Down-core samples of planktonic and benthic foraminifera were analyzed for oxygen and carbon isotopes in International Marine Past Global Changes Study (IMAGES) core MD99-2343 in order to study the interactions between climate change in the Northern Hemisphere and the western Mediterranean thermohaline circulation at times of Heinrich events (HE). Our results confirm the antiphase correlation between enhanced North Atlantic Deep Water formation and low ventilation in the Mediterranean. However, this study reveals that this antiphase relationship in deepwater formation between the North Atlantic and Mediterranean was interrupted during times of HE when the injection of large volumes of water from melting icebergs reached the entrance to the Mediterranean.... |
Tipo: Text |
Palavras-chave: Climatic change; Heinrich events; Mediterranean Sea; Carbon and oxygen isotopes; Thermohaline circulation; Pleistocene. |
Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34354/32759.pdf |
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Frajka-williams, Eleanor; Ansorge, Isabelle J.; Baehr, Johanna; Bryden, Harry L.; Chidichimo, Maria Paz; Cunningham, Stuart A.; Danabasoglu, Gokhan; Dong, Shenfu; Donohue, Kathleen A.; Elipot, Shane; Heimbach, Patrick; Holliday, N. Penny; Hummels, Rebecca; Jackson, Laura C.; Karstensen, Johannes; Lankhorst, Matthias; Le Bras, Isabela A.; Lozier, M. Susan; Mcdonagh, Elaine L.; Meinen, Christopher S.; Mercier, Herle; Moat, Bengamin I.; Perez, Renellys C; Piecuch, Christopher G.; Rhein, Monika; Srokosz, Meric A.; Trenberth, Kevin E.; Bacon, Sheldon; Forget, Gael; Goni, Gustavo; Kieke, Dagmar; Koelling, Jannes; Lamont, Tarron; Mccarthy, Gerard D.; Mertens, Christian; Send, Uwe; Smeed, David A.; Speich, Sabrina; Van Den Berg, Marcel; Volkov, Denis; Wilson, Chris. |
The Atlantic Meridional Overturning Circulation (AMOC) extends from the Southern Ocean to the northern North Atlantic, transporting heat northwards throughout the South and North Atlantic, and sinking carbon and nutrients into the deep ocean. Climate models indicate that changes to the AMOC both herald and drive climate shifts. Intensive trans-basin AMOC observational systems have been put in place to continuously monitor meridional volume transport variability, and in some cases, heat, freshwater and carbon transport. These observational programs have been used to diagnose the magnitude and origins of transport variability, and to investigate impacts of variability on essential climate variables such as sea surface temperature, ocean heat content and... |
Tipo: Text |
Palavras-chave: Meridional overturning circulation; Thermohaline circulation; Observing systems; Ocean heat transport; Carbon storage; Moorings; Circulation variability. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00503/61507/65342.pdf |
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Skinner, Lc; Shackleton, Nj. |
A sequence of accelerator mass spectrometry (AMS) C-14 dates performed on benthic and planktonic foraminifera from a northeast Atlantic deep-sea core (MD99-2334K; 37degrees480N, 10degrees10'W; 3146 m) permit the reconstruction of deep water ,,C-14 ventilation ages'' across the last deglaciation. The records from MD99-2334K have been placed on the GISP2 timescale via the synchrony of temperature changes recorded in the Greenland ice cores and in North Atlantic planktonic delta(18)O(cc) (calcite delta(18)O). On the basis of a range of estimates for past source water Delta(14)C, this permits the estimation of C-14 projection ventilation ages for comparison with benthic-planktonic C-14 age differences. Although the accurate estimation of past ventilation ages... |
Tipo: Text |
Palavras-chave: Termination I; Ventilation age; Thermohaline circulation. |
Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00228/33971/32339.pdf |
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Martínez, R.. |
Dentro de las actividades científicas contempladas en la VII Expedición Ecuatoriana a la Antártida para enero de 1998 en Buque de Investigación de la Armada B/I Orión efectuó un crucero oceanográfico en el Estrecho Branfield. Se efectuaron 14 estaciones oceanográficas hasta 500 metros, se realizaron mediciones de corriente utilizando un perfilador acústico doppler. Tomando como referencia trabajos anteriores en el área en años sin influencia de eventos cálidos se compararon los parámetros físicos. Luego del análisis se concluye que el evento ENSO 97-98 tuvo repercusiones evidentes en el área de estudio manifestada en dos aspectos básicos: El incremento de la temperatura y la disminución de la salinidad a nivel superficial. Esta variación habría generado un... |
Tipo: Journal Contribution |
Palavras-chave: Variability; Thermohaline circulation; Salinity; Water masses; El Nino phenomena; Cruises; Research vessels; Salinity. |
Ano: 1998 |
URL: http://hdl.handle.net/1834/3838 |
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Cornejo, María P.; Arcos, F.. |
Se determinaron algunas características físicas y biológicas de la columna de agua en Bahía Chile, Isla Greenwich, por medio de la distribución espacial de temperatura, salinidad y clorofila "a", durante el verano austral (febrero de 1990). Las distribuciones verticales de las isotermas, isohalinas, isopicnas e isolíneas de clorfila "a" muestran que la circulación predominante es termohalina, influenciada por la topografía de la bahía, con un flujo subsuperficial que entra por el lado noroccidental de la misma y se dirige hacia el centro (siguiendo la topografía), aflora en el extremo interior y sale superficialmente por el lado oriental. |
Tipo: Journal Contribution |
Palavras-chave: Chemical oceanography; Marine ecology; Salinity; Isotherms; Isopycnics; Thermohaline circulation; Chlorophylls; Chemical oceanography; Marine ecology; Salinity; Chlorophylls; Http://aims.fao.org/aos/agrovoc/c_1516; Http://aims.fao.org/aos/agrovoc/c_4609; Http://aims.fao.org/aos/agrovoc/c_6751; Http://aims.fao.org/aos/agrovoc/c_1577. |
Ano: 1990 |
URL: http://hdl.handle.net/1834/3728 |
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Registros recuperados: 24 | |
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