Patterns of millennial variability over the last 500 ka

• Published in: Climate of the Past
• Main Authors: Siddall, M, Rohling, Eelco, Blunier, T., Spahni, R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Copernicus GmbH
• Subjects: Keywords: atmospheric circulation; glacial debris; glacial history; glacial-interglacial cycle; ice sheet; iceberg; paleoclimate; sea ice; Antarctica; Dome Concordia; East Antarctica; Antarctic; Antarc*; EPICA; Ice Sheet; Iceberg*; North Atlantic; Sea ice
• Online Access: http://hdl.handle.net/1885/79256; https://doi.org/10.5194/cp-6-295-2010; https://openresearch-repository.anu.edu.au/bitstream/1885/79256/5/Rohling_E_2010_Patterns_of.pdf.jpg; https://openresearch-repository.anu.edu.au/bitstream/1885/79256/7/01_Siddall_Patterns_of_millennial_2010.pdf.jpg

Millennial variability is a robust feature of many paleoclimate records, at least throughout the last several glacial cycles. Here we use the mean signal from Antarctic climate events 1 to 4 to probe the EPICA Dome C temperature proxy reconstruction through the last 500 ka for similar millennial-scale events. We find that clusters of millennial events occurred in a regular fashion over half of the time during this with a mean recurrence interval of 21 kyr. We find that there is no consistent link between ice-rafted debris deposition and millennial variability. Instead we speculate that changes in the zonality of atmospheric circulation over the North Atlantic form a viable alternative to freshwater release from icebergs as a trigger for millennial variability. We suggest that millennial changes in the zonality of atmospheric circulation over the North Atlantic are linked to precession via sea-ice feedbacks and that this relationship is modified by the presence of the large, Northern Hemisphere ice sheets during glacial periods.