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| Titel |
Simulating ice core 10Be on the glacial–interglacial timescale |
| VerfasserIn |
C. Elsässer, D. Wagenbach, I. Levin, A. Stanzick, M. Christl, A. Wallner, S. Kipfstuhl, I. K. Seierstad, H. Wershofen, J. Dibb |
| 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. 2 ; Nr. 11, no. 2 (2015-02-03), S.115-133 |
| Datensatznummer |
250117158
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| Publikation (Nr.) |
 copernicus.org/cp-11-115-2015.pdf |
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| Zusammenfassung |
| 10Be ice core measurements are an important tool for paleoclimate
research, e.g., allowing for the reconstruction of past solar activity or
changes in the geomagnetic dipole field. However, especially on
multi-millennial timescales, the share of production and climate-induced
variations of respective 10Be ice core records is still up for debate.
Here we present the first quantitative climatological model of the 10Be
ice concentration up to the glacial–interglacial timescale. The model
approach is composed of (i) a coarse resolution global atmospheric transport
model and (ii) a local 10Be air–firn transfer model. Extensive
global-scale observational data of short-lived radionuclides as well as new
polar 10Be snow-pit measurements are used for model calibration and
validation. Being specifically configured for 10Be in polar ice, this
tool thus allows for a straightforward investigation of production- and
non-production-related modulation of this nuclide. We find that the polar
10Be ice concentration does not immediately record the globally mixed
cosmogenic production signal. Using geomagnetic modulation and revised
Greenland snow accumulation rate changes as model input, we simulate the
observed Greenland Summit (GRIP and GISP2) 10Be ice core records over
the last 75 kyr (on the GICC05modelext timescale). We show that our basic
model is capable of reproducing the largest portion of the observed 10Be
changes. However, model–measurement differences exhibit multi-millennial
trends (differences up to 87% in case of normalized to the Holocene records)
which call for closer investigation. Focusing on the (12–37) b2k
(before the year AD 2000) period, mean model–measurement differences of
30% cannot be attributed to production changes. However, unconsidered
climate-induced changes could likely explain the model–measurement mismatch.
In fact, the 10Be ice concentration is very sensitive to snow
accumulation changes. Here the reconstructed Greenland Summit (GRIP) snow
accumulation rate record would require revision of +28% to solely
account for the (12–37) b2k model–measurement differences. |
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