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Variability on the century time scale and regime changes in a stochastically forced zonally averaged ocean‐atmosphere model
Author(s) -
Aeberhardt Michael,
Blatter Marc,
Stocker Thomas F.
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl011103
Subject(s) - thermohaline circulation , forcing (mathematics) , climatology , atmosphere (unit) , shutdown of thermohaline circulation , ocean current , amplitude , north atlantic deep water , circulation (fluid dynamics) , environmental science , atmospheric sciences , geology , oceanography , physics , meteorology , mechanics , quantum mechanics
The response of a zonally averaged climate model of the atmosphere‐ocean system to a stochastic freshwater forcing depends on its strength. Three regimes are found: For small perturbations of the system, the ocean responds with irregular oscillations around a state which is characterized by a strong Atlantic overturning circulation. For intermediate to large amplitude forcing the thermohaline circulation in the Atlantic ocean exhibits pronounced regular overturning (flushing) events. The third regime is a complete collapse of the Atlantic overturning. Transitions can be induced between the three regimes. While for moderate values the transitions are reversible, for large forcing amplitudes the Atlantic overturning circulation collapses irreversibly to the third regime.