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| Titel |
Last interglacial temperature evolution – a model inter-comparison |
| VerfasserIn |
P. Bakker, E. J. Stone, S. Charbit, M. Gröger, U. Krebs-Kanzow, S. P. Ritz, V. Varma, V. Khon, D. J. Lunt, U. Mikolajewicz, M. Prange, H. Renssen, B. Schneider, M. Schulz |
| 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 ; 9, no. 2 ; Nr. 9, no. 2 (2013-03-11), S.605-619 |
| Datensatznummer |
250018009
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| Publikation (Nr.) |
 copernicus.org/cp-9-605-2013.pdf |
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| Zusammenfassung |
There is a growing number of proxy-based reconstructions detailing the
climatic changes that occurred during the last interglacial period (LIG). This
period is of special interest, because large parts of the globe were characterized
by a warmer-than-present-day climate, making this period an interesting test bed
for climate models in light of projected global warming. However, mainly
because synchronizing the different palaeoclimatic records is difficult, there is no
consensus on a global picture of LIG temperature changes. Here
we present the first model inter-comparison of transient simulations covering
the LIG period. By comparing the different simulations, we aim
at investigating the common signal in the LIG temperature evolution, investigating
the main driving forces behind it and at listing the climate feedbacks
which cause the most apparent inter-model differences.
The model inter-comparison shows a robust Northern Hemisphere July
temperature evolution characterized by a maximum between
130–125 ka BP with temperatures 0.3 to 5.3 K above
present day. A Southern Hemisphere July temperature maximum, −1.3
to 2.5 K at around 128 ka BP, is only found when changes
in the greenhouse gas concentrations are included. The robustness of simulated
January temperatures is large in the Southern Hemisphere and the
mid-latitudes of the Northern Hemisphere. For these regions maximum January
temperature anomalies of respectively −1 to 1.2 K and −0.8 to
2.1 K are simulated for the period after 121 ka BP. In both
hemispheres these temperature maxima are in line with the maximum in local
summer insolation.
In a number of specific regions, a common temperature evolution is not found
amongst the models. We show that this is related to feedbacks within the
climate system which largely determine the simulated LIG temperature
evolution in these regions. Firstly, in the Arctic region, changes in the summer
sea-ice cover control the evolution of LIG winter temperatures.
Secondly, for the Atlantic region, the Southern Ocean and the North Pacific,
possible changes in the characteristics of the Atlantic meridional overturning
circulation are crucial. Thirdly, the presence of remnant continental ice from the
preceding glacial has shown to be important when determining the timing of
maximum LIG warmth in the Northern Hemisphere. Finally, the results reveal
that changes in the monsoon regime exert a strong control on the evolution
of LIG temperatures over parts of Africa and India. By listing these inter-model
differences, we provide a starting point for future proxy-data studies and the
sensitivity experiments needed to constrain the climate simulations and to
further enhance our understanding of the temperature evolution of the
LIG period. |
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