|
|
|
| Registros recuperados: 12 | |
|
|
| Zumaque, J.; Eynaud, Frederique; Zaragosi, S.; Marret, F.; Matsuzaki, K. M.; Kissel, C.; Roche, D. M.; Malaize, B.; Michel, E.; Billy, I.; Richter, T.; Palis, E.. |
| The rapid climatic variability characterising the Marine Isotopic Stage (MIS) 3 (similar to 60-30 cal ka BP) provides key issues to understand the atmosphere-ocean-cryosphere dynamics. Here we investigate the response of sea-surface paleoenvironments to the MIS3 climatic variability through the study of a high resolution oceanic sedimentological archive (core MD99-2281, 60 degrees 21' N; 09 degrees 27' W; 1197m water depth), retrieved during the MD114-IMAGES (International Marine Global Change Study) cruise from the southern part of the Faeroe Bank. This sector was under the proximal influence of European ice sheets (Fennoscandian Ice Sheet to the East, British Irish Ice Sheet to the South) during the last glacial and thus probably responded to the MIS3... |
| Tipo: Text |
|
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00139/25060/23168.pdf |
| |
|
|
| Géli, Louis; Turon, J.-l.; Aslanian, Daniel; Balut, Y.; Beuzart, Paul; Cochran, J.; Francheteau, J.; Harmegnies, Francois; Landuré, Jean-yves; Le Suavé, Raymond; Mazaud, A.; Michel, E.; Normand, Alain; Pichon, Jack; Vlastelic, Ivan. |
| Tipo: Text |
|
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00288/39943/38491.pdf |
| |
|
|
| Guillevic, M.; Bazin, L.; Landais, A.; Stowasser, C.; Masson-delmotte, V.; Blunier, T.; Eynaud, F.; Falourd, S.; Michel, E.; Minster, B.; Popp, T.; Prie, F.; Vinther, M.. |
| Glacial climate was characterised by two types of abrupt events. Greenland ice cores record Dansgaard–Oeschger events, marked by abrupt warming in-between cold, stadial phases. Six of these stadials appear related to major Heinrich events (HEs), identified from ice-rafted debris (IRD) and large excursions in carbon- and oxygen-stable isotopic ratios in North Atlantic deep sea sediments, documenting major ice sheet collapse events. This finding has led to the paradigm that glacial cold events are induced by the response of the Atlantic Meridional Overturning Circulation to such massive freshwater inputs, supported by sensitivity studies conducted with climate models of various complexities. These models also simulate synchronous Greenland temperature and... |
| Tipo: Text |
|
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00293/40438/39539.pdf |
| |
|
|
| Bouttes, N.; Paillard, D.; Roche, D. M.; Waelbroeck, C.; Kageyama, M.; Lourantou, A.; Michel, E.; Bopp, L.. |
| During the last termination (from similar to 18 000 years ago to similar to 9000 years ago), the climate significantly warmed and the ice sheets melted. Simultaneously, atmospheric CO2 increased from similar to 190 ppm to similar to 260 ppm. Although this CO2 rise plays an important role in the deglacial warming, the reasons for its evolution are difficult to explain. Only box models have been used to run transient simulations of this carbon cycle transition, but by forcing the model with data constrained scenarios of the evolution of temperature, sea level, sea ice, NADW formation, Southern Ocean vertical mixing and biological carbon pump. More complex models (including GCMs) have investigated some of these mechanisms but they have only been used to try... |
| Tipo: Text |
|
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00214/32514/31004.pdf |
| |
|
|
| Lombard, F.; Labeyrie, L.; Michel, E.; Bopp, L.; Cortijo, E.; Retailleau, S.; Howa, Helene; Jorissen, F.. |
| We present an eco-physiological model reproducing the growth of eight foraminifer species (Neogloboquadrina pachyderma, Neogloboquadrina incompta, Neogloboquadrina dutertrei, Globigerina bulloides, Globigerinoides ruber, Globigerinoides sacculifer, Globigerinella siphonifera and Orbulina universa). By using the main physiological rates of foraminifers (nutrition, respiration, symbiotic photosynthesis), this model estimates their growth as a function of temperature, light availability, and food concentration. Model parameters are directly derived or calibrated from experimental observations and only the influence of food concentration (estimated via Chlorophyll-a concentration) was calibrated against field observations. Growth rates estimated from the model... |
| Tipo: Text |
|
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00249/36050/34585.pdf |
| |
|
|
| Caley, T.; Roche, D. M.; Waelbroeck, C.; Michel, E.. |
| We use the fully coupled atmosphere-ocean three-dimensional model of intermediate complexity iLOVECLIM to simulate the climate and oxygen stable isotopic signal during the Last Glacial Maximum (LGM, 21 000 years). By using a model that is able to explicitly simulate the sensor (delta O-18), results can be directly compared with data from climatic archives in the different realms. Our results indicate that iLOVECLIM reproduces well the main feature of the LGM climate in the atmospheric and oceanic components. The annual mean delta O-18 in precipitation shows more depleted values in the northern and southern high latitudes during the LGM. The model reproduces very well the spatial gradient observed in ice core records over the Greenland ice sheet. We observe... |
| Tipo: Text |
|
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00297/40871/39916.pdf |
| |
|
|
| Govin, A.; Braconnot, P.; Capron, E.; Cortijo, E.; Duplessy, J. -c.; Jansen, E.; Labeyrie, L.; Landais, A.; Marti, O.; Michel, E.; Mosquet, E.; Risebrobakken, B.; Swingedouw, D.; Waelbroeck, C.. |
| Although the Last Interglacial (LIG) is often considered as a possible analogue for future climate in high latitudes, its precise climate evolution and associated causes remain uncertain. Here we compile high-resolution marine sediment records from the North Atlantic, Labrador Sea, Norwegian Sea and the Southern Ocean. We document a delay in the establishment of peak interglacial conditions in the North Atlantic, Labrador and Norwegian Seas as compared to the Southern Ocean. In particular, we observe a persistent iceberg melting at high northern latitudes at the beginning of the LIG. It is associated with (1) colder and fresher surface-water conditions in the North Atlantic, Labrador and Norwegian Seas, and (2) a weaker ventilation of North Atlantic deep... |
| Tipo: Text |
|
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00266/37700/35848.pdf |
| |
|
|
| Tagliabue, A.; Bopp, L.; Roche, D. M.; Bouttes, N.; Dutay, J. -c.; Alkama, R.; Kageyama, M.; Michel, E.; Paillard, D.. |
| We use a state-of-the-art ocean general circulation and biogeochemistry model to examine the impact of changes in ocean circulation and biogeochemistry in governing the change in ocean carbon-13 and atmospheric CO2 at the last glacial maximum (LGM). We examine 5 different realisations of the ocean's overturning circulation produced by a fully coupled atmosphere-ocean model under LGM forcing and suggested changes in the atmospheric deposition of iron and phytoplankton physiology at the LGM. Measured changes in carbon-13 and carbon-14, as well as a qualitative reconstruction of the change in ocean carbon export are used to evaluate the results. Overall, we find that while a reduction in ocean ventilation at the LGM is necessary to reproduce carbon-13 and... |
| Tipo: Text |
|
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32919/31408.pdf |
| |
|
|
| Wary, M.; Eynaud, F.; Sabine, M.; Zaragosi, S.; Rossignol, L.; Malaize, B.; Palis, E.; Zumaque, J.; Caulle, C.; Penaud, A.; Michel, E.; Charlier, K.. |
| The last glacial period was punctuated by abrupt climatic events with extrema known as Heinrich and Dansgaard–Oeschger events. These millennial events have been the subject of many paleoreconstructions and model experiments in the past decades, but yet the hydrological processes involved remain elusive. In the present work, high-resolution analyses were conducted on the 12–42 ka BP section of core MD99-2281 retrieved southwest of the Faeroe Islands, and combined with analyses conducted in two previous studies (Zumaque et al., 2012; Caulle et al., 2013). Such a multiproxy approach, coupling micropaleontological, geochemical and sedimentological analyses, allows us to track surface, subsurface, and deep hydrological processes occurring during these rapid... |
| Tipo: Text |
|
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00296/40767/39770.pdf |
| |
|
|
| Dumont, M.; Pichevin, L.; Geibert, W.; Crosta, X.; Michel, E.; Moreton, S.; Dobby, K.; Ganeshram, R.. |
| Changes in ocean circulation and the biological carbon pump have been implicated as the drivers behind the rise in atmospheric CO2 across the last deglaciation; however, the processes involved remain uncertain. Previous records have hinted at a partitioning of deep ocean ventilation across the two major intervals of atmospheric CO2 rise, but the consequences of differential ventilation on the Si cycle has not been explored. Here we present three new records of silicon isotopes in diatoms and sponges from the Southern Ocean that together show increased Si supply from deep mixing during the deglaciation with a maximum during the Younger Dryas (YD). We suggest Antarctic sea ice and Atlantic overturning conditions favoured abyssal ocean ventilation at the YD... |
| Tipo: Text |
|
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00618/72971/72036.pdf |
| |
|
|
| Waelbroeck, C.; Skinner, L. C.; Labeyrie, L.; Duplessy, J. -c.; Michel, E.; Vazquez Riveiros, Natalia; Gherardi, J. M.; Dewilde, F.. |
| Well-dated benthic foraminifer oxygen isotopic records (delta O-18) from different water depths and locations within the Atlantic Ocean exhibit distinct patterns and significant differences in timing over the last deglaciation. This has two implications: on the one hand, it confirms that benthic delta O-18 cannot be used as a global correlation tool with millennial-scale precision, but on the other hand, the combination of benthic isotopic records with independent dating provides a wealth of information on past circulation changes. Comparing new South Atlantic benthic isotopic data with published benthic isotopic records, we show that (1) circulation changes first affected benthic delta O-18 in the 1000-2200 m range, with marked decreases in benthic delta... |
| Tipo: Text |
Palavras-chave: Atlantic Ocean; Benthic oxygen isotope; Last deglaciation; Ocean circulation. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00214/32517/31003.pdf |
| |
|
|
| Mazaud, A.; Kissel, C.; Laj, C.; Sicre, M. A.; Michel, E.; Turon, J. L.. |
| We examine the magnetic mineral deposition in three cores located at midlatitude sites in the South Indian Ocean, in an area where sediment eroded from the Kerguelen-Crozet plateau and transported by the marine currents, principally the Antarctic Circum Current, accumulates at a high sedimentation rate. We focus on Marine Isotopic Stage 3, characterized by large climatic fluctuations at northern latitudes, and compare the obtained records to the climatic records at Byrd ( Antarctica) and Summit (GISP2, Greenland) and to the North Atlantic Deep Water variations in the North Atlantic. Magnetic mineral deposition at the studied sites exhibits a profile with maxima at the time of Heinrich events H4 and H5, which suggests a strong Antarctic Circum Current when... |
| Tipo: Text |
Palavras-chave: Paleoceanography; South; Indian; Ocean; Paleoclimatology and paleoceanography; Environmental magnetism; Interhemispheric phasing. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00235/34612/32954.pdf |
| |
| Registros recuperados: 12 | |
|
|
|
