Clim. Past, 6, 295-303, 2010
www.clim-past.net/6/295/2010/
doi:10.5194/cp-6-295-2010
© Author(s) 2010. This work is distributed
under the Creative Commons Attribution 3.0 License.
Patterns of millennial variability over the last 500 ka
M. Siddall1, E. J. Rohling2, T. Blunier3, and R. Spahni4
1Department of Earth Science, University of Bristol, Bristol, UK
2National Oceanography Centre, Southampton, Southampton, UK
3Centre for Ice & Climate, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
4Climate and Environmental Physics and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland

Abstract. 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.

Citation: Siddall, M., Rohling, E. J., Blunier, T., and Spahni, R.: Patterns of millennial variability over the last 500 ka, Clim. Past, 6, 295-303, doi:10.5194/cp-6-295-2010, 2010.
 
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