University Of Tasmania
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Low-frequency oscillations of the Atlantic Ocean meridional overturning circulation in a coupled climate model

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journal contribution
posted on 2023-05-18, 01:01 authored by Schulz, M, Prange, M, Andreas KlockerAndreas Klocker
Using a 3-dimensional climate model of intermediate complexity we show that the overturning circulation of the Atlantic Ocean can vary at multicentennial-to-millennial timescales for modern boundary conditions. A continuous freshwater perturbation in the Labrador Sea pushes the overturning circulation of the Atlantic Ocean into a bi-stable regime, characterized by phases of active and inactive deepwater formation in the Labrador Sea. In contrast, deep-water formation in the Nordic Seas is active during all phases of the oscillations. The actual timing of the transitions between the two circulation states occurs randomly. The oscillations constitute a 3-dimensional phenomenon and have to be distinguished from low-frequency oscillations seen previously in 2-dimensional models of the ocean. A conceptual model provides further insight into the essential dynamics underlying the oscillations of the large-scale ocean circulation. The model experiments indicate that the coupled climate system can exhibit unforced climate variability at multicentennial-to-millennial timescales that may be of relevance for Holocene climate variations.


Publication title

Climate of the Past






Institute for Marine and Antarctic Studies


Copernicus Gesellschaft MBH

Place of publication


Rights statement

Copyright 2007 The Authors-distributed under the terms of Creative Commons License (CC BY 3.0).

Repository Status

  • Open

Socio-economic Objectives

Understanding climate change not elsewhere classified

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