A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years: GICC21
Ice-core timescales are vital for the understanding of past climate; hence they should be updated whenever significant amounts of new data can contribute to improvements. Here, the Greenland ice-core chronology was revised for the last 3835 years by synchronizing six deep ice-cores and three shallow...
Main Authors: | , , , , , , , , |
---|---|
Format: | Text |
Language: | English |
Published: |
2021
|
Subjects: | |
Online Access: | https://doi.org/10.5194/cp-2021-155 https://cp.copernicus.org/preprints/cp-2021-155/ |
id |
ftcopernicus:oai:publications.copernicus.org:cpd98994 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:cpd98994 2023-05-15T16:26:35+02:00 A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years: GICC21 Sinnl, Giulia Winstrup, Mai Erhardt, Tobias Cook, Eliza Jensen, Camilla Svensson, Anders Vinther, Bo Møllesøe Muscheler, Raimund Rasmussen, Sune Olander 2021-11-17 application/pdf https://doi.org/10.5194/cp-2021-155 https://cp.copernicus.org/preprints/cp-2021-155/ eng eng doi:10.5194/cp-2021-155 https://cp.copernicus.org/preprints/cp-2021-155/ eISSN: 1814-9332 Text 2021 ftcopernicus https://doi.org/10.5194/cp-2021-155 2021-11-22T17:22:30Z Ice-core timescales are vital for the understanding of past climate; hence they should be updated whenever significant amounts of new data can contribute to improvements. Here, the Greenland ice-core chronology 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 layer-counting bias was found in all ice cores because of site-specific signal disturbances, and a manual comparison of all ice cores was deemed necessary to increase timescale accuracy. A new method was applied by combining automated counting of annual layers on multiple parallel proxies and manual fine-tuning. After examining sources of error and their correlation lengths, the uncertainty rate was quantified to be one year per century. The new timescale is younger than the previous Greenland chronology by about 13 years at 3800 years ago. The most recent 800 years are largely unaffected by the revision, while the slope of the offset between timescales is steepest between 800 and 1000 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 data set available to this study, and to the finer resolution of the new ice-core matching. In response to volcanic eruptions, averaged water isotopes and layer thicknesses from Greenland ice cores provide evidence of notable cooling lasting for up to a decade, longer than reported in previous studies of volcanic forcing. By analysis of the common variations of cosmogenic radionuclides, the new ice-core timescale is found to be in alignment with the IntCal20 curve. Radiocarbon dated evidence found in the proximity of eruption sites such as Vesuvius or Thera was compared to the ice-core dataset; no conclusive evidence was found regarding if these two eruptions can be matched to acidity spikes in the ice cores. A hitherto unidentified cooling event in the ice cores is observed at about 3600 years ago (1600 BCE), which could have been caused by a large eruption which is, however, not clearly recorded in the acidity signal. The hunt for clear signs of the Thera eruption in Greenland ice-cores thus remains elusive. Text Greenland Greenland ice core Greenland ice cores ice core Ice Sheet Copernicus Publications: E-Journals Greenland |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Ice-core timescales are vital for the understanding of past climate; hence they should be updated whenever significant amounts of new data can contribute to improvements. Here, the Greenland ice-core chronology 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 layer-counting bias was found in all ice cores because of site-specific signal disturbances, and a manual comparison of all ice cores was deemed necessary to increase timescale accuracy. A new method was applied by combining automated counting of annual layers on multiple parallel proxies and manual fine-tuning. After examining sources of error and their correlation lengths, the uncertainty rate was quantified to be one year per century. The new timescale is younger than the previous Greenland chronology by about 13 years at 3800 years ago. The most recent 800 years are largely unaffected by the revision, while the slope of the offset between timescales is steepest between 800 and 1000 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 data set available to this study, and to the finer resolution of the new ice-core matching. In response to volcanic eruptions, averaged water isotopes and layer thicknesses from Greenland ice cores provide evidence of notable cooling lasting for up to a decade, longer than reported in previous studies of volcanic forcing. By analysis of the common variations of cosmogenic radionuclides, the new ice-core timescale is found to be in alignment with the IntCal20 curve. Radiocarbon dated evidence found in the proximity of eruption sites such as Vesuvius or Thera was compared to the ice-core dataset; no conclusive evidence was found regarding if these two eruptions can be matched to acidity spikes in the ice cores. A hitherto unidentified cooling event in the ice cores is observed at about 3600 years ago (1600 BCE), which could have been caused by a large eruption which is, however, not clearly recorded in the acidity signal. The hunt for clear signs of the Thera eruption in Greenland ice-cores thus remains elusive. |
format |
Text |
author |
Sinnl, Giulia Winstrup, Mai Erhardt, Tobias Cook, Eliza Jensen, Camilla Svensson, Anders Vinther, Bo Møllesøe Muscheler, Raimund Rasmussen, Sune Olander |
spellingShingle |
Sinnl, Giulia Winstrup, Mai Erhardt, Tobias Cook, Eliza Jensen, Camilla Svensson, Anders Vinther, Bo Møllesøe Muscheler, Raimund Rasmussen, Sune Olander A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years: GICC21 |
author_facet |
Sinnl, Giulia Winstrup, Mai Erhardt, Tobias Cook, Eliza Jensen, Camilla Svensson, Anders Vinther, Bo Møllesøe Muscheler, Raimund Rasmussen, Sune Olander |
author_sort |
Sinnl, Giulia |
title |
A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years: GICC21 |
title_short |
A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years: GICC21 |
title_full |
A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years: GICC21 |
title_fullStr |
A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years: GICC21 |
title_full_unstemmed |
A multi-ice-core, annual-layer-counted Greenland ice-core chronology for the last 3800 years: GICC21 |
title_sort |
multi-ice-core, annual-layer-counted greenland ice-core chronology for the last 3800 years: gicc21 |
publishDate |
2021 |
url |
https://doi.org/10.5194/cp-2021-155 https://cp.copernicus.org/preprints/cp-2021-155/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Greenland ice core Greenland ice cores ice core Ice Sheet |
genre_facet |
Greenland Greenland ice core Greenland ice cores ice core Ice Sheet |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-2021-155 https://cp.copernicus.org/preprints/cp-2021-155/ |
op_doi |
https://doi.org/10.5194/cp-2021-155 |
_version_ |
1766015513761153024 |