The DO-climate events are noise induced: statistical investigation of the claimed 1470 years cycle

• Main Authors: Ditlevsen, P. D., Andersen, K. K., Svensson, A.
• Other Authors: Niels Bohr Institute Copenhagen (NBI), Faculty of Science Copenhagen, University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Greenland; Greenland ice cores; NGRIP
• Online Access: https://hal.archives-ouvertes.fr/hal-00298164; https://hal.archives-ouvertes.fr/hal-00298164/document; https://hal.archives-ouvertes.fr/hal-00298164/file/cpd-2-1277-2006.pdf

International audience 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.