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| Titel |
A first chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core |
| VerfasserIn |
S. O. Rasmussen, P. M. Abbott, T. Blunier, A. J. Bourne, E. Brook, S. L. Buchardt, C. Buizert, J. Chappellaz, H. B. Clausen, E. Cook, D. Dahl-Jensen, S. M. Davies, M. Guillevic, S. Kipfstuhl, T. Laepple, I. K. Seierstad, J. P. Severinghaus, J. P. Steffensen, C. Stowasser, A. Svensson, P. Vallelonga, B. M. Vinther, F. Wilhelms, M. Winstrup |
| 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. 6 ; Nr. 9, no. 6 (2013-12-05), S.2713-2730 |
| Datensatznummer |
250085270
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| Publikation (Nr.) |
 copernicus.org/cp-9-2713-2013.pdf |
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| Zusammenfassung |
A stratigraphy-based chronology for the North Greenland Eemian Ice Drilling
(NEEM) ice core has been derived by transferring the annual layer counted
Greenland Ice Core Chronology 2005 (GICC05) and its model extension
(GICC05modelext) from the NGRIP core to the NEEM core using 787 match points
of mainly volcanic origin identified in the electrical conductivity
measurement (ECM) and dielectrical profiling (DEP) records. Tephra horizons
found in both the NEEM and NGRIP ice cores are used to test the matching
based on ECM and DEP and provide five additional horizons used for the timescale transfer.
A thinning function reflecting the accumulated strain along the core has
been determined using a Dansgaard–Johnsen flow model and an
isotope-dependent accumulation rate parameterization. Flow parameters are
determined from Monte Carlo analysis constrained by the observed depth-age
horizons.
In order to construct a chronology for the gas phase, the ice age–gas age
difference (Δage) has been reconstructed using a coupled firn
densification-heat diffusion model. Temperature and accumulation inputs to
the Δage model, initially derived from the water isotope proxies, have
been adjusted to optimize the fit to timing constraints from δ15N
of nitrogen and high-resolution methane data during the abrupt onset of
Greenland interstadials.
The ice and gas chronologies and the corresponding thinning function
represent the first chronology for the NEEM core, named
GICC05modelext-NEEM-1. Based on both the flow and firn modelling results,
the accumulation history for the NEEM site has been reconstructed. Together,
the timescale and accumulation reconstruction provide the necessary basis
for further analysis of the records from NEEM. |
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