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Sessford, E. G.; Tisserand, A. A.; Risebrobakken, B.; Andersson, C.; Dokken, T.; Jansen, E.. |
Dansgaard-Oeschger (D-O) climate instabilities that took place during Marine Isotope Stage 3 are connected to changes in ocean circulation patterns and sea ice cover. Here we explore in detail the configuration of the water column of the Denmark Strait during D-O events 8-5. How the ocean currents and water masses within the Denmark Strait region responded and were connected to the North Atlantic are discussed. We investigate sediment core GS15-198-36CC, from the northern side of the Greenland-Iceland Ridge, at 30-year temporal resolution. Stable carbon and oxygen isotope reconstructions based on benthic foraminifera, together with a high-resolution benthic foraminiferal record of Mg/Ca paleothermometry, is presented. The site was bathed by warm... |
Tipo: Text |
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Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00504/61589/65890.pdf |
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Andersson, C.; Pausata, F. S. R.; Jansen, E.; Risebrobakken, B.; Telford, R. J.. |
The early to mid-Holocene thermal optimum is a well-known feature in a wide variety of paleoclimate archives from the Northern Hemisphere. Reconstructed summer temperature anomalies from across northern Europe show a clear maximum around 6000 years before present (6 ka). For the marine realm, Holocene trends in sea-surface temperature reconstructions for the North Atlantic and Norwegian Sea do not exhibit a consistent pattern of early to mid-Holocene warmth. Sea-surface temperature records based on alkenones and diatoms generally show the existence of a warm early to mid-Holocene optimum. In contrast, several foraminifer and radiolarian based temperature records from the North Atlantic and Norwegian Sea show a cool mid-Holocene anomaly and a trend towards... |
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Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00231/34254/32636.pdf |
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Smith, Y. M.; Hill, D. J.; Dolan, A. M.; Haywood, A. M.; Dowsett, H. J.; Risebrobakken, B.. |
The Arctic cryosphere is changing and making a significant contribution to sea level rise. The Late Pliocene had similar CO2 levels to the present and a warming comparable to model predictions for the end of this century. However, the state of the Arctic cryosphere during the Pliocene remains poorly constrained. For the first time we combine outputs from a climate model with a thermodynamic iceberg model to simulate likely source regions for ice-rafted debris (IRD) found in the Nordic Seas from Marine Isotope Stage M2 to the mid-Piacenzian Warm Period and what this implies about the nature of the Arctic cryosphere at this time. We compare the fraction of melt given by the model scenarios with IRD data from four Ocean Drilling Program sites in the Nordic... |
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Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00504/61593/65884.pdf |
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Born, A.; Nisancioglu, K. H.; Risebrobakken, B.. |
We analyze a transient simulation of the last glacial inception in a climate model of intermediate complexity, focusing on sea ice-ocean circulation dynamics in the North Atlantic and Nordic Seas. As northern high-latitude summer insolation decreases toward the end of the Eemian interglacial, Arctic sea ice export to the North Atlantic increases. This surface fresh water transport weakens deep water formation in the North Atlantic and the near-surface circulation of the subpolar gyre. As a consequence, the relative contribution of subpolar gyre waters to the Atlantic inflow into the Nordic Seas is reduced, giving way to more warm and saline subtropical waters from the North Atlantic Current. We thus find an episode of relatively high heat and salt... |
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Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00227/33858/32375.pdf |
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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... |
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Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00266/37700/35848.pdf |
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