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A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years : GICC21

Sinnl, Giulia LU ; Winstrup, Mai ; Erhardt, Tobias ; Cook, Eliza ; Jensen, Camilla Marie ; Svensson, Anders ; Vinther, Bo Møllesøe ; Muscheler, Raimund LU orcid and Rasmussen, Sune Olander (2022) In Climate of the Past 18(5). p.1125-1150
Abstract

Ice-core timescales are vital for the understanding of past climate; hence they should be updated whenever significant amounts of new data become available. Here, the Greenland ice-core chronology GICC05 was revised for the last 3835 years by synchronizing six deep ice cores and three shallow ice cores from the central Greenland ice sheet. A new method was applied by combining automated counting of annual layers on multiple parallel proxies and manual fine-tuning. A layer counting bias was found in all ice cores because of site-specific signal disturbances; therefore the manual comparison of all ice cores was deemed necessary to increase timescale accuracy. After examining sources of error and their correlation lengths, the uncertainty... (More)

Ice-core timescales are vital for the understanding of past climate; hence they should be updated whenever significant amounts of new data become available. Here, the Greenland ice-core chronology GICC05 was revised for the last 3835 years by synchronizing six deep ice cores and three shallow ice cores from the central Greenland ice sheet. A new method was applied by combining automated counting of annual layers on multiple parallel proxies and manual fine-tuning. A layer counting bias was found in all ice cores because of site-specific signal disturbances; therefore the manual comparison of all ice cores was deemed necessary to increase timescale accuracy. After examining sources of error and their correlation lengths, the uncertainty rate was quantified to be 1 year per century. The new timescale is younger than GICC05 by about 13 years at 3835 years ago. The most recent 800 years are largely unaffected by the revision. Between 800 and 2000 years ago, the offset between timescales increases steadily, with the steepest offset occurring between 800 and 1100 years ago. Moreover, offset oscillations of about 5 years around the average are observed between 2500 and 3800 years ago. The non-linear offset behavior is attributed to previous mismatches of volcanic eruptions, to the much more extensive dataset available to this study, and to the finer resolution of the new ice-core ammonium matching. By analysis of the common variations in cosmogenic radionuclides, the new ice-core timescale is found to be in alignment with the IntCal20 curve (Reimer et al., 2020).

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Climate of the Past
volume
18
issue
5
pages
26 pages
publisher
Copernicus GmbH
external identifiers
  • scopus:85131088959
ISSN
1814-9324
DOI
10.5194/cp-18-1125-2022
language
English
LU publication?
yes
id
93382c79-e637-4247-9f9c-0d7143eadda3
date added to LUP
2023-01-03 15:49:14
date last changed
2023-05-10 11:24:20
@article{93382c79-e637-4247-9f9c-0d7143eadda3,
  abstract     = {{<p>Ice-core timescales are vital for the understanding of past climate; hence they should be updated whenever significant amounts of new data become available. Here, the Greenland ice-core chronology GICC05 was revised for the last 3835 years by synchronizing six deep ice cores and three shallow ice cores from the central Greenland ice sheet. A new method was applied by combining automated counting of annual layers on multiple parallel proxies and manual fine-tuning. A layer counting bias was found in all ice cores because of site-specific signal disturbances; therefore the manual comparison of all ice cores was deemed necessary to increase timescale accuracy. After examining sources of error and their correlation lengths, the uncertainty rate was quantified to be 1 year per century. The new timescale is younger than GICC05 by about 13 years at 3835 years ago. The most recent 800 years are largely unaffected by the revision. Between 800 and 2000 years ago, the offset between timescales increases steadily, with the steepest offset occurring between 800 and 1100 years ago. Moreover, offset oscillations of about 5 years around the average are observed between 2500 and 3800 years ago. The non-linear offset behavior is attributed to previous mismatches of volcanic eruptions, to the much more extensive dataset available to this study, and to the finer resolution of the new ice-core ammonium matching. By analysis of the common variations in cosmogenic radionuclides, the new ice-core timescale is found to be in alignment with the IntCal20 curve (Reimer et al., 2020).</p>}},
  author       = {{Sinnl, Giulia and Winstrup, Mai and Erhardt, Tobias and Cook, Eliza and Jensen, Camilla Marie and Svensson, Anders and Vinther, Bo Møllesøe and Muscheler, Raimund and Rasmussen, Sune Olander}},
  issn         = {{1814-9324}},
  language     = {{eng}},
  number       = {{5}},
  pages        = {{1125--1150}},
  publisher    = {{Copernicus GmbH}},
  series       = {{Climate of the Past}},
  title        = {{A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years : GICC21}},
  url          = {{http://dx.doi.org/10.5194/cp-18-1125-2022}},
  doi          = {{10.5194/cp-18-1125-2022}},
  volume       = {{18}},
  year         = {{2022}},
}