Publikationen

Simulating ice core Be-10 on the glacial-interglacial timescale

Autor(en)
C. Elsässer, D. Wagenbach, I. Levin, A. Stanzick, M. Christl, A. Wallner, S. Kipfstuhl, I. K. Seierstad, H. Wershofen, J. Dibb
Abstrakt

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 transportmodel 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 polar10Be 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.

Organisation(en)
Isotopenphysik
Externe Organisation(en)
Ruprecht-Karls-Universität Heidelberg, Eidgenössische Technische Hochschule Zürich, Physikalisch-Technische Bundesanstalt (PTB), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, University of Copenhagen, University of New Hampshire
Journal
Climate of the Past
Band
11
Seiten
115-133
Anzahl der Seiten
19
ISSN
1814-9324
DOI
https://doi.org/10.5194/cp-11-115-2015
Publikationsdatum
2015
Peer-reviewed
Ja
ÖFOS 2012
103014 Kernphysik, 105204 Klimatologie
Schlagwörter
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/simulating-ice-core-be10-on-the-glacialinterglacial-timescale(bea0c95c-60bc-4e05-bd6a-c18bc1f253a6).html