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| Bagniewski, Witold; Meissner, Katrin J.; Menviel, Laurie; Brennan, Catherine E.. |
| We perform idealized experiments of a Heinrich Stadial using an oxygen-isotope-enabled Earth System Climate Model. Our results compare relatively well with the planktic and benthic delta O-18 records of Heinrich Stadials 1 and 4. We find that changes in surface delta O-18(c) can be equally attributed to the "temperature effect" due to fractionation during calcification; the "circulation and climate effect" due to changes in circulation, precipitation, and evaporation; and the "meltwater effect" due to the addition and subsequent advection of depleted fresh water from continental ice sheets. In contrast, the meltwater effect and circulation and climate effect have only a small impact on benthic delta O-18(c) during the cessation of the Atlantic Meridional... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00351/46253/46085.pdf |
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| Bengtson, Shannon A.; Menviel, Laurie C.; Meissner, Katrin J.; Missiaen, Lise; Peterson, Carlye D.; Lisiecki, Lorraine E.; Joos, Fortunat. |
| The last time in Earth's history when high latitudes were warmer than during pre-industrial times was the last interglacial period (LIG, 129–116 ka BP). Since the LIG is the most recent and best documented interglacial, it can provide insights into climate processes in a warmer world. However, some key features of the LIG are not well constrained, notably the oceanic circulation and the global carbon cycle. Here, we use a new database of LIG benthic δ13C to investigate these two aspects. We find that the oceanic mean δ13C was ∼ 0.2 ‰ lower during the LIG (here defined as 125–120 ka BP) when compared to the Holocene (7–2 ka BP). A lower terrestrial carbon content at the LIG than during the Holocene could have led to both lower oceanic δ13C and atmospheric... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79397/81928.pdf |
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| Bagniewski, Witold; Meissner, Katrin J.; Menviel, Laurie. |
| We present the first transient simulations of Marine Isotope Stage 3 (MIS 3) performed with an oxygen isotope-enabled climate model. Our simulations span several Dansgaard-Oeschger cycles and three Heinrich stadials and are directly compared with oxygen isotope records from 13 sediment and 2 ice cores. Our results are consistent with a 30-50% weakening of the Atlantic Meridional Overturning Circulation during Dansgaard-Oeschger stadials and a complete shutdown during Heinrich stadials. We find that the simulated delta O-18 anomalies differ significantly between Heinrich stadials and non-Heinrich stadials. This difference is mainly due to different responses in ocean circulation, and therefore climate, impacting oceanic delta O-18, while the volume of... |
| Tipo: Text |
Palavras-chave: MIS3; Model-data comparison; Heinrich events; Dansgaard-Oeschger cycles; Delta O-18; AMOC. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00420/53180/55067.pdf |
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