The tempo of climate change during Dansgaard-Oeschger interstadials and its potential to affect the manifestation of the 1470-year climate cycle

Abstract

The oxygen-isotope record from the GISP2 ice core serves a air-temperature proxy to estimate cooling rates during Dansgaard-Oeschger interstadials between 15-53 thousand years before present. The duration of individual Dansgaard-Oeschger interstadials scales inversely with the cooling rate and high cooling rates are associated with large continental ice volume and vice versa. Cooling rates determine the extent to which the postulated 1470-year pacing cycle of the Dansgaard-Oeschger interstadials is visible in paleoclimatological records: Only cooling rates associated with intermediate ice volume (approx. -84 ± 20 m relative sea-level equivalent) allow the climate system to respond to succeeding trigger events of the 1470-year cycle and result in stadials/interstadials of nearly the same duration. INDEX TERMS: 3344 Meteorology and Atmospheric Dynamics: Paleoclimatology, 4267 Ocenography: General: Paleoceano-graphy.