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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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 |
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Copernicus Publications: E-Journals |
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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 |
_version_ |
1766017413258674176 |