Ice-shelf collapse from subsurface warming as a trigger for Heinrich events.
In: Proceedings of the National Academy of Sciences of the United States of America, Jg. 108 (2011-08-16), Heft 33, S. 13415
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Zugriff:
Episodic iceberg-discharge events from the Hudson Strait Ice Stream (HSIS) of the Laurentide Ice Sheet, referred to as Heinrich events, are commonly attributed to internal ice-sheet instabilities, but their systematic occurrence at the culmination of a large reduction in the Atlantic meridional overturning circulation (AMOC) indicates a climate control. We report Mg/Ca data on benthic foraminifera from an intermediate-depth site in the northwest Atlantic and results from a climate-model simulation that reveal basin-wide subsurface warming at the same time as large reductions in the AMOC, with temperature increasing by approximately 2 °C over a 1-2 kyr interval prior to a Heinrich event. In simulations with an ocean model coupled to a thermodynamically active ice shelf, the increase in subsurface temperature increases basal melt rate under an ice shelf fronting the HSIS by a factor of approximately 6. By analogy with recent observations in Antarctica, the resulting ice-shelf loss and attendant HSIS acceleration would produce a Heinrich event.
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Ice-shelf collapse from subsurface warming as a trigger for Heinrich events.
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Autor/in / Beteiligte Person: | Marcott, SA ; Clark, PU ; Padman, L ; Klinkhammer, GP ; Springer, SR ; Liu, Z ; Otto-Bliesner, BL ; Carlson, AE ; Ungerer, A ; Padman, J ; He, F ; Cheng, J ; Schmittner, A |
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Zeitschrift: | Proceedings of the National Academy of Sciences of the United States of America, Jg. 108 (2011-08-16), Heft 33, S. 13415 |
Veröffentlichung: | Washington, DC : National Academy of Sciences, 2011 |
Medientyp: | academicJournal |
ISSN: | 1091-6490 (electronic) |
DOI: | 10.1073/pnas.1104772108 |
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