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The DO-climate events are noise induced: statistical investigation of the claimed 1470 years cycle
The Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen O, Denmark
Abstract. The significance of the apparent 1470 years cycle in the recurrence of the Dansgaard-Oeschger (DO) events, observed in the Greenland ice cores, is debated. Here we present statistical significance tests of this periodicity. The detection of a periodicity relies strongly on the accuracy of the dating of the DO events. Here we use both the new NGRIP GICC05 time scale based on multi-parameter annual layer counting and the GISP2 time scale where the periodicity is most pronounced. For the NGRIP dating the recurrence times are indistinguishable from a random occurrence. This is also the case for the GISP2 dating, except in the case where the DO9 event is omitted from the record. Whether or not the record shows a truly periodic beating has strong implications for identifying the underlying cause. If the recurrence is periodic it suggests an external cause. If the recurrence of DO events is not periodic it points to triggering mechanisms internal to the climate system being manifested at the millennial timescale.
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Citation: Ditlevsen, P. D., Andersen, K. K., and Svensson, A.: The DO-climate events are noise induced: statistical investigation of the claimed 1470 years cycle, Clim. Past Discuss., 2, 1277-1292, 2006. Bibtex EndNote Reference Manager
