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| Gu, Sifan; Liu, Zhengyu; Zhang, Jiaxu; Rempfer, Johannes; Joos, Fortunat; Oppo, Delia W.. |
| Antarctic Intermediate Water (AAIW) plays important roles in the global climate system and the global ocean nutrient and carbon cycles. However, it is unclear how AAIW responds to global climate changes. In particular, neodymium isotopic composition (epsilon(Nd)) reconstructions from different locations from the tropical Atlantic have led to a debate on the relationship between northward penetration of AAIW into the tropical Atlantic and the Atlantic meridional overturning circulation (AMOC) variability during the last deglaciation. We resolve this controversy by studying the transient oceanic evolution during the last deglaciation using a neodymium-enabled ocean model. Our results suggest a coherent response of AAIW and AMOC: when AMOC weakens, the... |
| Tipo: Text |
Palavras-chave: AAIW; AMOC; Deglacial; Neodymium isotope; Paleocirculation tracer. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00495/60709/65334.pdf |
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| Capuano, Tonia Astrid; Speich, Sabrina; Carton, Xavier; Laxenaire, Remi. |
| This study evaluates the capability of eddy-permitting regional ocean models to reproduce the interocean exchange south of Africa. In this highly turbulent region, we show that the vertical structure of the horizontal flows need to be appropriately resolved to realistically advect thermocline water masses into the South Atlantic. Our results point out that a grid-spacing of 1/24 degrees on the horizontal and 50 m on the vertical homogeneously distributed are required to account for a correct transport of surface and subsurface water masses properties and their in-route transformation by mixing. Preliminary Lagrangian analyses highlight the primary role of the upper-ocean mesoscale eddies on water masses transport and fate, with a particular emphasis on... |
| Tipo: Text |
Palavras-chave: Eddy dynamics; Indo-Atlantic exchange; AAIW. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00600/71245/69616.pdf |
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| Ronge, Thomas Alexander. |
| Reconstructions on Antarctic ice cores revealed pronounced, millennial-scale variabilities in atmospheric CO2 over the past 800,000 years (e.g. Lüthi et al., 2008; Monnin et al., 2001; Petit et al., 1999; Raynaud et al., 2005; Siegenthaler et al., 2005). Despite these variabilities are known for several decades, the mechanisms, driving these patterns are still not fully resolved. As the ocean contains up to 60 times more carbon than the entire atmosphere, it is considered to be a major driver of the atmospheric CO2 levels (Broecker, 1982): Storing CO2 during glacials, releasing it during deglaciations. Because changes in the global thermohaline circulation are thought to operate on glacial/interglacial timescales, it has been suggested that during... |
| Tipo: Text |
Palavras-chave: 14C; Ventilation; Atmospheric CO2; AAIW; UCDW; LCDW; AABW. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00493/60453/63898.pdf |
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| Martinez-mendez, G.; Hebbeln, D.; Mohtadi, M.; Lamy, F.; De Pol-holz, R.; Reyes-macaya, D.; Freudenthal, Tim. |
| The Antarctic Intermediate Water (AAIW) is a key player in global-scale oceanic overturning processes and an important conduit for heat, fresh water, and carbon transport. The AAIW past variability is poorly understood mainly due to the lack of sedimentary archives at intermediate water depths. We present records of benthic stable isotopes from sediments retrieved with the seafloor drill rig MARUM-MeBo at 956m water depth off northern Chile (GeoB15016, 27 degrees 29.48S, 71 degrees 07.58W) that extend back to 970ka. The sediments at this site are presently deposited at the boundary between AAIW and Pacific Deep Water (PDW). For previous peak interglacials, our results reveal similar benthic C-13 values at site GeoB15016 and of a newly generated stack of... |
| Tipo: Text |
Palavras-chave: Paleoceanography; AAIW; Advection changes. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00263/37459/35821.pdf |
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| Ronge, Thomas A.; Steph, Silke; Tiedemann, Ralf; Prange, Matthias; Merkel, Ute; Nuernberg, Dirk; Kuhn, Gerhard. |
| Glacial/interglacial changes in Southern Ocean's air-sea gas exchange have been considered as important mechanisms contributing to the glacial/interglacial variability in atmospheric CO2. Hence, understanding past variability in Southern Ocean intermediate to deep water chemistry and circulation is fundamental to constrain the role of these processes on modulating glacial/interglacial changes in the global carbon cycle. Our study focused on the glacial/interglacial variability in the vertical extent of southwest Pacific Antarctic Intermediate Water (AAIW). We compared carbon and oxygen isotope records from epibenthic foraminifera of sediment cores bathed in modern AAIW and Upper Circumpolar Deep Water (UCDW; 943–2066 m water depth) to monitor changes in... |
| Tipo: Text |
Palavras-chave: AAIW; UCDW; SW-Pacific; Stable isotopes. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00294/40568/39465.pdf |
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