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| Titel |
Factors controlling the last interglacial climate as simulated by LOVECLIM1.3 |
| VerfasserIn |
M. F. Loutre, T. Fichefet, H. Goosse, P. Huybrechts, H. Goelzer, E. Capron |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 10, no. 4 ; Nr. 10, no. 4 (2014-08-27), S.1541-1565 |
| Datensatznummer |
250117027
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| Publikation (Nr.) |
 copernicus.org/cp-10-1541-2014.pdf |
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| Zusammenfassung |
The last interglacial (LIG), also identified to the Eemian in Europe, began
at approximately 130 kyr BP and ended at about 115 kyr BP (before
present). More and more proxy-based reconstructions of the LIG climate are
becoming more available even though they remain sparse. The major climate forcings during
the LIG are rather well known and therefore models can be tested against
paleoclimatic data sets and then used to better understand the climate of the
LIG. However, models are displaying a large range of responses, being
sometimes contradictory between them or with the reconstructed data. Here we
would like to investigate causes of these differences. We focus on a single
climate model, LOVECLIM, and we perform transient simulations over the LIG,
starting at 135 kyr BP and run until 115 kyr BP. With these simulations,
we test the role of the surface boundary conditions (the time-evolution of
the Northern Hemisphere (NH) ice sheets) on the simulated LIG climate and the
importance of the parameter sets (internal to the model, such as the albedos
of the ocean and sea ice), which affect the sensitivity of the model.
The magnitude of the simulated climate variations through the LIG remains too
low compared to reconstructions for climate variables such as surface air
temperature. Moreover, in the North Atlantic, the large increase in summer
sea surface temperature towards the peak of the interglacial occurs too early
(at ∼128 kyr BP) compared to the reconstructions. This feature as
well as the climate simulated during the optimum of the LIG, between 131 and
121 kyr BP, does not depend on changes in surface boundary conditions and
parameter sets.
The additional freshwater flux (FWF) from the melting NH ice sheets is
responsible for a temporary abrupt weakening of the North Atlantic
meridional overturning circulation, which causes a strong global cooling in
annual mean. However, the changes in the configuration (extent and albedo)
of the NH ice sheets during the LIG only slightly impact the simulated
climate. Together, configuration of and FWF from the NH ice sheets greatly
increase the magnitude of the temperature variations over continents as well
as over the ocean at the beginning of the simulation and reduce the
difference between the simulated climate and the reconstructions. Lastly, we
show that the contribution from the parameter sets to the climate response
is actually very modest. |
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