In:
Climate of the Past, Copernicus GmbH, Vol. 19, No. 7 ( 2023-07-21), p. 1447-1459
Abstract:
Abstract. During the Late Pleistocene, Dansgaard–Oeschger (DO)
cycles triggered warming events that were as abrupt as the present-day
human-induced warming. However, in the absence of a periodic forcing operating on millennial timescales, 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 (δ18Oice) record; a 123 kyr long proxy record of air temperatures (Tair) over Greenland. For both modes of DO cyclicity – slow and fast – we detect disparate energy sources. Slow DO cycles, marked by multi-millennial periodicities in the 12.5 to 2.5 kyr bandwidth, receive energy from astronomical periodicities. Fast DO cycles, characterized by millennial periodicities in the 1.5 ± 0.5 kyr range, 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 timescales to explain the origins of climate cycles without primary periodic energy sources.
Type of Medium:
Online Resource
ISSN:
1814-9332
DOI:
10.5194/cp-19-1447-2023
DOI:
10.5194/cp-19-1447-2023-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2217985-9
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