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| Wary, Melanie; Eynaud, Frederique; Swingedouw, Didier; Masson-delmotte, Valerie; Matthiessen, Jens; Kissel, Catherine; Zumaque, Jena; Rossignol, Linda; Jouzel, Jean. |
| Dansgaard-Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48-30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00420/53149/55328.pdf |
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| Bouttes, Nathaelle; Swingedouw, Didier; Roche, Didier M.; Sanchez-goni, Maria F.; Crosta, Xavier. |
| Atmospheric CO2 levels during interglacials prior to the Mid-Brunhes Event (MBE, similar to 430 kaBP) were around 40 ppm lower than after the MBE. The reasons for this difference remain unclear. A recent hypothesis proposed that changes in oceanic circulation, in response to different external forcings before and after the MBE, might have increased the ocean carbon storage in pre-MBE interglacials, thus lowering atmospheric CO2. Nevertheless, no quantitative estimate of this hypothesis has been produced up to now. Here we use an intermediate complexity model including the carbon cycle to evaluate the response of the carbon reservoirs in the atmosphere, ocean and land in response to the changes of orbital forcings, ice sheet configurations and atmospheric... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00497/60821/65114.pdf |
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