Disparate energy sources for slow and fast Dansgaard-Oeschger cycles

During the Late Pleistocene, Dansgaard-Oeschger (DO) cycles triggered warming events that were as abrupt as the present-day human-induced warming. However, in absence of a periodic forcing operating on millennial time scales, the main energy sources of DO cycles remain debated. Here, we identify the...

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Main Authors: Liebrand, Diederik, Bakker, Anouk T. M., Johnstone, Heather J. H., Miller, Charlotte S.
Format: Text
Language:English
Published: 2023
Subjects:
Online Access:https://doi.org/10.5194/cp-2023-6
https://cp.copernicus.org/preprints/cp-2023-6/
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spelling ftcopernicus:oai:publications.copernicus.org:cpd109611 2023-05-15T16:27:51+02:00 Disparate energy sources for slow and fast Dansgaard-Oeschger cycles Liebrand, Diederik Bakker, Anouk T. M. Johnstone, Heather J. H. Miller, Charlotte S. 2023-02-24 application/pdf https://doi.org/10.5194/cp-2023-6 https://cp.copernicus.org/preprints/cp-2023-6/ eng eng doi:10.5194/cp-2023-6 https://cp.copernicus.org/preprints/cp-2023-6/ eISSN: 1814-9332 Text 2023 ftcopernicus https://doi.org/10.5194/cp-2023-6 2023-02-27T17:22:57Z During the Late Pleistocene, Dansgaard-Oeschger (DO) cycles triggered warming events that were as abrupt as the present-day human-induced warming. However, in absence of a periodic forcing operating on millennial time scales, the main energy sources of DO cycles remain debated. Here, we identify the energy sources of DO cycles by applying a bispectral analysis to the North Greenland ice core project (NGRIP) oxygen isotope (δ 18 O ice ) record—a 123-thousand-years (kyr) long proxy-record of air-temperatures (T air ) over Greenland. For both modes of DO cyclicity—slow and fast—we detect disparate energy sources. Slow-DO cycles are marked by multi-millennial periodicities in the 12.5 to 2.5 kyr bandwidth and receive energy from astronomical periodicities. Fast-DO cycles have millennial periodicities in the 1.5 ± 0.5 kyr range and receive energy from centennial periodicities. We propose cryospheric and oceanic mechanisms that facilitate the transfer of energy from known sources to slow- and fast-DO cycles, respectively. Our findings stress the importance of understanding energy-transfer mechanisms across a broad range of time scales to explain the origins of climate cycles without primary periodic energy-sources. Text Greenland Greenland ice core Greenland Ice core Project ice core NGRIP North Greenland North Greenland Ice Core Project Copernicus Publications: E-Journals Greenland
institution Open Polar
collection Copernicus Publications: E-Journals
op_collection_id ftcopernicus
language English
description During the Late Pleistocene, Dansgaard-Oeschger (DO) cycles triggered warming events that were as abrupt as the present-day human-induced warming. However, in absence of a periodic forcing operating on millennial time scales, the main energy sources of DO cycles remain debated. Here, we identify the energy sources of DO cycles by applying a bispectral analysis to the North Greenland ice core project (NGRIP) oxygen isotope (δ 18 O ice ) record—a 123-thousand-years (kyr) long proxy-record of air-temperatures (T air ) over Greenland. For both modes of DO cyclicity—slow and fast—we detect disparate energy sources. Slow-DO cycles are marked by multi-millennial periodicities in the 12.5 to 2.5 kyr bandwidth and receive energy from astronomical periodicities. Fast-DO cycles have millennial periodicities in the 1.5 ± 0.5 kyr range and receive energy from centennial periodicities. We propose cryospheric and oceanic mechanisms that facilitate the transfer of energy from known sources to slow- and fast-DO cycles, respectively. Our findings stress the importance of understanding energy-transfer mechanisms across a broad range of time scales to explain the origins of climate cycles without primary periodic energy-sources.
format Text
author Liebrand, Diederik
Bakker, Anouk T. M.
Johnstone, Heather J. H.
Miller, Charlotte S.
spellingShingle Liebrand, Diederik
Bakker, Anouk T. M.
Johnstone, Heather J. H.
Miller, Charlotte S.
Disparate energy sources for slow and fast Dansgaard-Oeschger cycles
author_facet Liebrand, Diederik
Bakker, Anouk T. M.
Johnstone, Heather J. H.
Miller, Charlotte S.
author_sort Liebrand, Diederik
title Disparate energy sources for slow and fast Dansgaard-Oeschger cycles
title_short Disparate energy sources for slow and fast Dansgaard-Oeschger cycles
title_full Disparate energy sources for slow and fast Dansgaard-Oeschger cycles
title_fullStr Disparate energy sources for slow and fast Dansgaard-Oeschger cycles
title_full_unstemmed Disparate energy sources for slow and fast Dansgaard-Oeschger cycles
title_sort disparate energy sources for slow and fast dansgaard-oeschger cycles
publishDate 2023
url https://doi.org/10.5194/cp-2023-6
https://cp.copernicus.org/preprints/cp-2023-6/
geographic Greenland
geographic_facet Greenland
genre Greenland
Greenland ice core
Greenland Ice core Project
ice core
NGRIP
North Greenland
North Greenland Ice Core Project
genre_facet Greenland
Greenland ice core
Greenland Ice core Project
ice core
NGRIP
North Greenland
North Greenland Ice Core Project
op_source eISSN: 1814-9332
op_relation doi:10.5194/cp-2023-6
https://cp.copernicus.org/preprints/cp-2023-6/
op_doi https://doi.org/10.5194/cp-2023-6
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