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| Menviel, Laurie; Capron, Emilie; Govin, Aline; Dutton, Andrea; Tarasov, Lev; Abe-ouchi, Ayako; Drysdale, Russell; Gibbard, Philip; Gregoire, Lauren; He, Feng; Ivanovic, Ruza; Kageyama, Masa; Kawamura, Kenji; Landais, Amaelle; Otto-bliesner, Bette L.; Oyabu, Ikumi; Tzedakis, Polychronis; Wolff, Eric; Zhang, Xu. |
| The penultimate deglaciation (~ 138–128 thousand years before present, hereafter ka) is the transition from the penultimate glacial maximum to the Last Interglacial (LIG, ~ 129–116 ka). The LIG stands out as one of the warmest interglacials of the last 800 ka, with high-latitude temperature warmer than today and global sea level likely higher by at least 6 meters. The LIG therefore receives ever-growing attention, in particular to identify mechanisms and feedbacks responsible for such regional warmth that is comparable to that expected before 2100. Considering the transient nature of the Earth system, the LIG climate and ice-sheets evolution were certainly influenced by the changes occurring during the penultimate deglaciation. It is thus important to... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00491/60241/63638.pdf |
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| Menviel, Laurie; Capron, Emilie; Govin, Aline; Dutton, Andrea; Tarasov, Lev; Abe-ouchi, Ayako; Drysdale, Russell N.; Gibbard, Philip L.; Gregoire, Lauren; He, Feng; Ivanovic, Ruza F.; Kageyama, Masa; Kawamura, Kenji; Landais, Amaelle; Otto-bliesner, Bette L.; Oyabu, Ikumi; Tzedakis, Polychronis C.; Wolff, Eric; Zhang, Xu. |
| The penultimate deglaciation (PDG, ∼138–128 thousand years before present, hereafter ka) is the transition from the penultimate glacial maximum (PGM) to the Last Interglacial (LIG, ∼129–116 ka). The LIG stands out as one of the warmest interglacials of the last 800 000 years (hereafter kyr), with high-latitude temperature warmer than today and global sea level likely higher by at least 6 m. Considering the transient nature of the Earth system, the LIG climate and ice-sheet evolution were certainly influenced by the changes occurring during the penultimate deglaciation. It is thus important to investigate, with coupled atmosphere–ocean general circulation models (AOGCMs), the climate and environmental response to the large changes in boundary conditions... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00511/62284/66502.pdf |
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| Riveiros, Natalia Vazquez; Govin, Aline; Waelbroeck, Claire; Mackensen, Andreas; Michel, Elisabeth; Moreira, Santiago; Bouinot, Thomas; Caillon, Nicolas; Orgun, Ayche; Brandon, Margaux. |
| Planktic foraminiferal Mg/Ca ratios have become a fundamental seawater temperature proxy in past climate reconstructions, due to the temperature dependence of Mg uptake into foraminiferal calcite. However, empirical calibrations for single species from methodologically consistent data are still lacking. Here we present species-specific calibrations of Mg/Ca versus calcification temperature for two commonly used species of planktic foraminifera: Globigerina bulloides and Neogloboquadrina pachyderma left, based on a series of Southern Ocean and North Atlantic core tops. Combining these new data with previously published data, we derive an integrated G. bulloides Mg/Ca-temperature calibration for mid and high latitudes of both hemispheres between 2 and 18°C,... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00324/43480/42916.pdf |
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| Govin, Aline; Varma, Vidya; Prange, Matthias. |
| This study documents the long-term evolution of western African precipitation during the Last Interglacial (LIG). We compare geochemical records obtained on nine sediment cores from the western African margin to a transient simulation (130–115 ka) performed with an ocean-atmosphere general circulation model and insolation as sole forcing. Good agreement between proxy records and model outputs indicates that long-term changes in western African precipitation largely responded to insolation variations during most of the LIG. After an early LIG dry phase (related to high-latitude iceberg melting or dating uncertainties), boreal summer insolation controlled the intensification of the North African monsoon between 127 and 122 ka, perhaps facilitating human... |
| Tipo: Text |
Palavras-chave: Last Interglacial; Africa; Precipitation; Astronomical forcing; Marine sediment cores; Model simulations. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40164/38778.pdf |
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| Govin, Aline; Holzwarth, Ulrike; Heslop, David; Keeling, Lara Ford; Zabel, Matthias; Mulitza, Stefan; Collins, James A.; Chiessi, Cristiano M.. |
| Numerous studies use major element concentrations measured on continental margin sediments to reconstruct terrestrial climate variations. The choice and interpretation of climate proxies however differ from site to site. Here we map the concentrations of major elements (Ca, Fe, Al, Si, Ti, K) in Atlantic surface sediments (36 degrees N-49 degrees S) to assess the factors influencing the geochemistry of Atlantic hemipelagic sediments and the potential of elemental ratios to reconstruct different terrestrial climate regimes. High concentrations of terrigenous elements and low Ca concentrations along the African and South American margins reflect the dominance of terrigenous input in these regions. Single element concentrations and elemental ratios including... |
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Palavras-chave: Atlantic surface sediments; Terrigenous input; Major elements. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00214/32550/31035.pdf |
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| Capron, Emilie; Govin, Aline; Stone, Emma J.; Masson-delmotte, Valerie; Mulitza, Stefan; Otto-bliesner, Bette; Rasmussen, Tine L.; Sime, Louise C.; Waelbroeck, Claire; Wolff, Eric W.. |
| The Last Interglacial (LIG, 129-116 thousand of years BP, ka) represents a test bed for climate model feedbacks in warmer-than-present high latitude regions. However, mainly because aligning different palaeoclimatic archives and from different parts of the world is not trivial, a spatio-temporal picture of LIG temperature changes is difficult to obtain. Here, we have selected 47 polar ice core and sub-polar marine sediment records and developed a strategy to align them onto the recent AICC2012 ice core chronology. We provide the first compilation of high-latitude temperature changes across the LIG associated with a coherent temporal framework built between ice core and marine sediment records. Our new data synthesis highlights non-synchronous maximum... |
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Palavras-chave: Last Interglacial period; Marine sediment cores; Ice cores; Data synthesis; Climate model simulations. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00289/40063/39166.pdf |
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| Govin, Aline; Michel, Elisabeth; Labeyrie, Laurent; Waelbroeck, Claire; Dewilde, Fabien; Jansen, Eystein. |
| We investigated deep water changes in the Southern Ocean during the last glacial inception, in relationship to surface hydrology and global climatology, to better understand the mechanisms of the establishment of a glacial ocean circulation. Changes in benthic foraminiferal delta(13)C from three high-resolution cores are compared and indicate decoupled intermediate and deep water changes in the Southern Ocean. From the comparison with records from the North Atlantic, South Atlantic, and the Southern Ocean, we show that the early southern deep water delta(13)C drop observed at the MIS 5.5-5.4 transition occurred before any significant reduction of North Atlantic Deep Water ventilation. We propose that this drop is linked to the northward expansion of poorly... |
| Tipo: Text |
Palavras-chave: Isotope substage 5E; Ice core; Interglacial period; Climate variability; Deep ocean; Atlantic; Sea; Circulation; Temperature; Hemisphere. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00208/31952/30375.pdf |
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| Burckel, Pierre; Waelbroeck, Claire; Luo, Yiming; Roche, Didier M.; Pichat, Sylvain; Jaccard, Samuel L.; Gherardi, Jeanne; Govin, Aline; Lippold, Jörg; Thil, Francois. |
| We reconstruct the geometry and strength of the Atlantic meridional overturning circulation during the Heinrich stadial 2 and three Greenland interstadials of the 2050 ka period based on the comparison of new and published sedimentary Pa-231/Th-230 data with simulated sedimentary Pa-231/Th-230. We show that the deep Atlantic circulation during these interstadials was very different from that of the Holocene. Northern-sourced waters likely circulated above 2500 m depth, with a flow rate lower than that of the present-day North Atlantic deep water (NADW). Southern-sourced deep waters most probably flowed northwards below 4000 m depth into the North Atlantic basin and then southwards as a return flow between 2500 and 4000 m depth. The flow rate of this... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53212/54867.pdf |
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