Publikationen

Simulating ice core <sup>10</sup>Be 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): Universität Heidelberg, Eidgenössische Technische Hochschule Zürich, Physikalisch-Technische Bundesanstalt, 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
ASJC Scopus Sachgebiete: Global and Planetary Change, Palaeontology, Stratigraphy
Sustainable Development Goals: SDG 13 – Maßnahmen zum Klimaschutz
Link zum Portal: https://ucris.univie.ac.at/portal/de/publications/simulating-ice-core-10be-on-the-glacialinterglacial-timescale(bea0c95c-60bc-4e05-bd6a-c18bc1f253a6).html