Hindcasting the continuum of Dansgaard-Oeschger variability: Mechanisms, patterns and timing

Millennial-scale variability associated with Dansgaard-Oeschger events is arguably one of the most puzzling climate phenomena ever discovered in paleoclimate archives. Here, we set out to elucidate the underlying dynamics by conducting a transient global hindcast simulation with a 3-D intermediate c...

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Bibliographic Details
Published in:Climate of the Past
Main Authors: Menviel, L, Timmermann, A, Friedrich, T, England, MH
Format: Article in Journal/Newspaper
Language:unknown
Published: Copernicus Publications 2014
Subjects:
Online Access:http://hdl.handle.net/1959.4/unsworks_13563
https://doi.org/10.5194/cp-10-63-2014
Description
Summary:Millennial-scale variability associated with Dansgaard-Oeschger events is arguably one of the most puzzling climate phenomena ever discovered in paleoclimate archives. Here, we set out to elucidate the underlying dynamics by conducting a transient global hindcast simulation with a 3-D intermediate complexity earth system model covering the period 50 to 30 ka BP. The model is forced by time-varying external boundary conditions (greenhouse gases, orbital forcing, and ice-sheet orography and albedo) and anomalous North Atlantic freshwater fluxes, which mimic the effects of changing northern hemispheric ice volume on millennial timescales. Together these forcings generate a realistic global climate trajectory, as demonstrated by an extensive model/paleo data comparison. Our results are consistent with the idea that variations in ice-sheet calving and subsequent changes of the Atlantic Meridional Overturning Circulation were the main drivers for the continuum of glacial millennial-scale variability seen in paleorecords across the globe. © Author(s) 2014.