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A signature of persistent natural thermohaline circulation cycles in observed climate
Author(s) -
Knight Jeff R.,
Allan Robert J.,
Folland Chris K.,
Vellinga Michael,
Mann Michael E.
Publication year - 2005
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 - 10.1029/2005gl024233
Subject(s) - atlantic multidecadal oscillation , predictability , thermohaline circulation , climatology , climate model , climate change , natural (archaeology) , environmental science , abrupt climate change , geology , global warming , oceanography , effects of global warming , paleontology , physics , quantum mechanics
Analyses of global climate from measurements dating back to the nineteenth century show an ‘Atlantic Multidecadal Oscillation’ (AMO) as a leading large‐scale pattern of multidecadal variability in surface temperature. Yet it is not possible to determine whether these fluctuations are genuinely oscillatory from the relatively short observational record alone. Using a 1400 year climate model calculation, we are able to simulate the observed pattern and amplitude of the AMO. The results imply the AMO is a genuine quasi‐periodic cycle of internal climate variability persisting for many centuries, and is related to variability in the oceanic thermohaline circulation (THC). This relationship suggests we can attempt to reconstruct past THC changes, and we infer an increase in THC strength over the last 25 years. Potential predictability associated with the mode implies natural THC and AMO decreases over the next few decades independent of anthropogenic climate change.