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| Titel |
Simulating the vegetation response in western Europe to abrupt climate changes under glacial background conditions |
| VerfasserIn |
M.-N. Woillez, M. Kageyama, N. Combourieu-Nebout, G. Krinner |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 3 ; Nr. 10, no. 3 (2013-03-07), S.1561-1582 |
| Datensatznummer |
250018142
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| Publikation (Nr.) |
 copernicus.org/bg-10-1561-2013.pdf |
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| Zusammenfassung |
The last glacial period has been punctuated by two types of abrupt climatic
events, the Dansgaard–Oeschger (DO) and Heinrich (HE) events. These events,
recorded in Greenland ice and in marine sediments, involved changes in the
Atlantic Meridional Overturning Circulation (AMOC) and led to major changes
in the terrestrial biosphere.
Here we use the dynamical global vegetation model ORCHIDEE to simulate the
response of vegetation to abrupt changes in the AMOC strength. We force
ORCHIDEE offline with outputs from the IPSL_CM4 general circulation model,
in which the AMOC is forced to change by adding freshwater fluxes in the
North Atlantic. We investigate the impact of a collapse and recovery of the
AMOC, at different rates, and focus on Western Europe, where many pollen
records are available for comparison.
The impact of an AMOC collapse on the European mean temperatures and
precipitations simulated by the GCM is relatively small but sufficient to
drive an important regression of forests and expansion of grasses in
ORCHIDEE, in qualitative agreement with pollen data for an HE event. On the
contrary, a run with a rapid shift of the AMOC to a hyperactive state of
30 Sv, mimicking the warming phase of a DO event, does not exhibit a strong
impact on the European vegetation compared to the glacial control state. For
our model, simulating the impact of an HE event thus appears easier than
simulating the abrupt transition towards the interstadial phase of a DO.
For both a collapse or a recovery of the AMOC, the vegetation starts to
respond to climatic changes immediately but reaches equilibrium about 200 yr
after the climate equilibrates, suggesting a possible bias in the climatic
reconstructions based on pollen records, which assume equilibrium between
climate and vegetation. However, our study does not take into account
vegetation feedbacks on the atmosphere. |
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