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| Titel |
Comparing past accumulation rate reconstructions in East Antarctic ice cores using 10Be, water isotopes and CMIP5-PMIP3 models |
| VerfasserIn |
A. Cauquoin, A. Landais, G. M. Raisbeck, J. Jouzel, L. Bazin, M. Kageyama, J.-Y. Peterschmitt, M. Werner, E. Bard, Aster Team |
| 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 ; 11, no. 3 ; Nr. 11, no. 3 (2015-03-05), S.355-367 |
| Datensatznummer |
250117204
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| Publikation (Nr.) |
 copernicus.org/cp-11-355-2015.pdf |
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| Zusammenfassung |
| Ice cores are exceptional archives which allow us to reconstruct
a wealth of climatic parameters as well as past atmospheric
composition over the last 800 kyr in Antarctica. Inferring the
variations in past accumulation rate in polar regions is essential
both for documenting past climate and for ice core chronology. On
the East Antarctic Plateau, the accumulation rate is so small that
annual layers cannot be identified and accumulation rate is mainly
deduced from the water isotopic composition assuming constant
temporal relationships between temperature, water isotopic
composition and accumulation rate. Such an assumption leads to large
uncertainties on the reconstructed past accumulation rate. Here, we
use high-resolution beryllium-10 (10Be) as an alternative
tool for inferring past accumulation rate for the EPICA Dome C ice
core, in East Antarctica. We present a high-resolution
10Be record covering a full climatic cycle over the period
269 to 355 ka from Marine Isotope Stage (MIS) 9 to 10, including a period warmer than pre-industrial (MIS 9.3 optimum).
After correcting 10Be for the estimated effect of
the palaeomagnetic field, we deduce that the 10Be
reconstruction is in reasonably good agreement with EDC3 values for the full
cycle except for the period warmer than present. For the latter, the accumulation is up to
13% larger (4.46 cm ie yr−1 instead of 3.95).
This result is in agreement with the studies
suggesting an underestimation of the deuterium-based accumulation
for the optimum of the Holocene (Parrenin et al. 2007a). Using the relationship
between accumulation rate and surface temperature from the saturation vapour
relationship, the 10Be-based accumulation rate reconstruction suggests that
the temperature increase between the MIS 9.3 optimum and present day may be 2.4 K
warmer than estimated by the water isotopes reconstruction. We compare these reconstructions
to the available model results from CMIP5-PMIP3 for a glacial and an interglacial state,
i.e. for the Last Glacial Maximum and pre-industrial climates. While 3 out of 7 models
show relatively good agreement with the reconstructions of the accumulation–temperature
relationships based on 10Be and water isotopes, the other models either
underestimate or overestimate it, resulting in a range of model results much larger
than the range of the reconstructions. Indeed, the models can encounter some difficulties in simulating precipitation changes linked with temperature or water isotope content on the East
Antarctic Plateau during glacial–interglacial transition and need to be improved in the future. |
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