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Registros recuperados: 14 | |
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Durgadoo, Jonathan V.; Loveday, Benjamin R.; Reason, Chris J. C.; Penven, Pierrick; Biastoch, Arne. |
The Agulhas Current plays a crucial role in the thermohaline circulation through its leakage into the South Atlantic Ocean. Under both past and present climates, the trade winds and westerlies could have the ability to modulate the amount of Indian-Atlantic inflow. Compelling arguments have been put forward suggesting that trade winds alone have little impact on the magnitude of Agulhas leakage. Here, employing three ocean models for robust analysisa global coarse-resolution, a regional eddy-permitting, and a nested high-resolution eddy-resolving configurationand systematically altering the position and intensity of the westerly wind belt in a series of sensitivity experiments, it is shown that the westerlies, in particular their intensity, control the... |
Tipo: Text |
Palavras-chave: Boundary currents; Meridional overturning circulation; Wind stress; Mesoscale models; Numerical analysis; Modeling. |
Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00161/27247/25452.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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Fernández-castro, Bieito; Álvarez, Marta; Nieto-cid, Mar; Zunino, Patricia; Mercier, Herle; Álvarez-salgado, Xosé Antón. |
Dissolved organic matter (DOM) is produced in the surface and exported towards the deep ocean, adding ∼2 PgC yr−1 to the global carbon export. Due to its central role in the Meridional Overturning Circulation (MOC), the eastern subpolar North Atlantic (eSPNA) contributes largely to this export. Here we quantify the transport and budget of dissolved organic nitrogen (DON) in the eSPNA, in a box delimited by the OVIDE 2002 section and the Greenland‐Iceland‐Scotland sills. The MOC exports >15.9 TgN yr−1 of DON downwards and, contrary to the extended view that these are materials of subtropical origin, up to 33% of the vertical flux derives from a net local DON production of 7.1 ± 2.6 TgN yr−1. The low C:N molar ratio of DOM production (7.4 ± 4.1) and the... |
Tipo: Text |
Palavras-chave: Dissolved organic matter; Nitrogen cycle; Meridional overturning circulation; Subpolar North Atlantic; Metabolic balance. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00485/59622/62649.pdf |
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Meinen, Christopher S.; Speich, Sabrina; Piola, Alberto R.; Ansorge, Isabelle; Campos, Edmo; Kersale, Marion; Terre Terrillon, Thierry; Chidichimo, Maria Paz; Lamont, Tarron; Sato, Olga T.; Perez, Renellys C.; Valla, Daniel; Van Den Berg, Marcel; Le Henaff, Matthieu; Dong, Shenfu; Garzoli, Silvia L.. |
Six years of simultaneous moored observations near the western and eastern boundaries of the South Atlantic are combined with satellite winds to produce a daily time series of the basin-wide meridional overturning circulation (MOC) volume transport at 34.5 degrees S. The results demonstrate that barotropic and baroclinic signals at both boundaries cause significant transport variations, and as such must be concurrently observed. The data, spanning similar to 20 months during 2009-2010 and similar to 4 years during 2013-2017, reveal a highly energetic MOC record with a temporal standard deviation of 8.3 Sv, and strong variations at time scales ranging from a few days to years (peak-to-peak range = 54.6 Sv). Seasonal transport variations are found to have... |
Tipo: Text |
Palavras-chave: Meridional overturning circulation; South Atlantic; Overturning; Volume transport; Observations. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00445/55612/57253.pdf |
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Meinen, Christopher S.; Speich, Sabrina; Perez, Renellys C.; Dong, Shenfu; Piola, Alberto R.; Garzoli, Silvia L.; Gladyshev, Sergey; Baringer, Molly; Campos, Edmo J. D.. |
Data from two boundary arrays deployed along 34.5°S are combined to produce the first continuous in situ time series observations of the basin-wide meridional overturning circulation (MOC) in the South Atlantic. Daily estimates of the MOC between March 2009 and December 2010 range between 3 Sv and 39 Sv (1 Sv = 106 m3 s−1) after a 10 day low-pass filter is applied. Much of the variability in this ∼20 month record occurs at periods shorter than 100 days. Approximately two-thirds of the MOC variability is due to changes in the geostrophic (baroclinic plus barotropic) volume transport, with the remainder associated with the direct wind-forced Ekman transport. When low-pass filtered to match previously published analyses in the North Atlantic, the observed... |
Tipo: Text |
Palavras-chave: Meridional overturning circulation; Transport; South Atlantic; Inverted echo sounder; Bottom pressure. |
Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00167/27789/25982.pdf |
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Liu, Wei; Fedorov, Alexey; Sevellec, Florian. |
We explore the mechanisms by which Arctic sea ice decline affects the Atlantic meridional overturning circulation (AMOC) in a suite of numerical experiments perturbing the Arctic sea ice radiative budget within a fully coupled climate model. The imposed perturbations act to increase the amount of heat available to melt ice, leading to a rapid Arctic sea ice retreat within 5 years after the perturbations are activated. In response, the AMOC gradually weakens over the next similar to 100 years. The AMOC changes can be explained by the accumulation in the Arctic and subsequent downstream propagation to the North Atlantic of buoyancy anomalies controlled by temperature and salinity. Initially, during the first decade or so, the Arctic sea ice loss results in... |
Tipo: Text |
Palavras-chave: Arctic; Meridional overturning circulation; Climate models. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00599/71107/69388.pdf |
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Registros recuperados: 14 | |
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