Abrupt climate change due to mode switches between three circulation modes of the glacial Atlantic


 
Schematic representation of three modes of operation of the climate system during the Last Ice Age.

The large Earth in the centre shows the stable cold (or "stadial") climate state prevailing during most of the Ice Age.
Below it is the situation during a warm Dansgaard-Oeschger (D/O) event, in which the Atlantic conveyor belt temporarily advances into the Nordic Seas and a strong warm anomaly develops there (contours). 
The upper globe shows climate during a Heinrich event, with collapsed conveyor belt and a cold anomaly over the mid-latitude Atlantic.
The continental ice cover shown is the reconstruction of Peltier, prescribed as a boundary condition in the model simulations.
 

  • For a more detailed description of the three modes, see our paper: Ganopolski, A. and S. Rahmstorf, 2001: Simulation of rapid glacial climate changes in a coupled climate model. Nature, 409, 153-158. 

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  • A more popular description is found in our press release.

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  • This paper is also discussed in a Nature News & Views by Didier Paillard.

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  • You can watch a movie of these events: a D/O event followed by a Heinrich event and another D/O event.

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  • Mode switches could be caused by an interesting  mechanism called 'stochastic resonance'. This is analysed in: Ganopolski, A. and S. Rahmstorf, 2001: Abrupt glacial climate changes due to stochastic resonance. Phys. Rev. Let., in press.

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