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| Bugelmayer-blaschek, Marianne; Roche, Didier M.; Renssen, Hans; Andrews, John T.. |
| The climate of the Holocene, the current interglacial covering the past 11,700 years, has been relatively stable compared to previous periods. Nevertheless, repeating occurrence of rapid natural climate changes that challenged human society are seen in proxy reconstructions. Ocean sediment cores for example display prominent peaks of enhanced ice rafted debris (IRD) during the Holocene with a multidecadal to millennial scale periodicity. Different mechanisms were proposed that caused these enhanced IRD events, for example variations in the incoming total solar irradiance (TSI), volcanic eruptions and the combination of internal climate variability and external forcings. We investigate the probable mechanisms causing the occurrence of IRD-events over the... |
| Tipo: Text |
Palavras-chave: Greenland ice sheet; Holocene; Bond events; Icebergs; Climate modeling. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53253/54711.pdf |
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| Wiersma, Ane P.; Jongma, Jochem I.. |
| We investigate the potential role of icebergs in the 8.2 ka climate event, using a coupled climate model equipped with an iceberg component. First, we evaluate the effect of a large iceberg discharge originating from the decaying Laurentide ice sheet on ocean circulation, compared to a release of an identical volume of freshwater alone. Our results show that, on top of the freshwater effect, a large iceberg discharge facilitates sea-ice growth as a result of lower sea-surface temperatures induced by latent heat of melting. This causes an 8% increased sea-ice cover, 5% stronger reduction in North Atlantic Deep Water production and 1A degrees C lower temperature in Greenland. Second, we use the model to investigate the effect of a hypothetical two-stage lake... |
| Tipo: Text |
Palavras-chave: 8.2 ka event; Climate modeling; Icebergs; Laurentide ice sheet; Hudson Strait; Holocene; Heinrich events. |
| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00496/60749/65152.pdf |
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| Keller, Kathrin M.; Joos, Fortunat; Raible, Christoph C.; Cocco, Valentina; Froelicher, Thomas L.; Dunne, John P.; Gehlen, Marion; Bopp, Laurent; Orr, James C.; Tjiputra, Jerry; Heinze, Christoph; Segschneider, Joachim; Roy, Tilla; Metzl, Nicolas. |
| Climate modes such as the North Atlantic Oscillation (NAO), representing internal variability of the climate system, influence the ocean carbon cycle and may mask trends in the sink of anthropogenic carbon. Here, utilising control runs of six fully coupled Earth System Models, the response of the ocean carbon cycle to the NAO is quantified. The dominating response, a seesaw pattern between the subtropical gyre and the subpolar Northern Atlantic, is instantaneous (<3 months) and dynamically consistent over all models and with observations for a range of physical and biogeochemical variables. All models show asymmetric responses to NAO+ and NAO− forcing, implying non-linearity in the connection between NAO and the ocean carbon cycle. However, model... |
| Tipo: Text |
Palavras-chave: North Atlantic Oscillation; Carbon cycle; Ocean biogeochemistry; Climate modeling; Ocean-atmosphere interaction. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00140/25166/23272.pdf |
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