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The Arctic and Antarctic oscillations and their projected changes under global warming
Author(s) -
Fyfe J. C.,
Boer G. J.,
Flato G. M.
Publication year - 1999
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 - 10.1029/1999gl900317
Subject(s) - antarctic oscillation , climatology , northern hemisphere , arctic oscillation , southern hemisphere , forcing (mathematics) , climate change , environmental science , climate model , global warming , oscillation (cell signaling) , arctic , atmospheric sciences , greenhouse gas , latitude , geology , oceanography , genetics , geodesy , biology
The Arctic Oscillation (AO) and the Antarctic Oscillation (AAO) are the leading modes of high‐latitude variability in each hemisphere as characterized by the first EOF of mean sea‐level pressure. Observations suggest a recent positive trend in the AO and it is speculated that this may be related to global warming. The CCCma coupled general circulation model control simulation exhibits a robust and realistic AO and AAO. Climate change simulations for the period 1900–2100, with forcing due to greenhouse gases and aerosols, exhibit positive trends in both the AO and the AAO. The model simulates essentially unchanged AO/AAO variations superimposed on a forced climate change pattern. The results do not suggest that a simulated trend in the AO/AAO necessarily depends on stratospheric involvement nor that forced climate change will be expressed as a change in the occurence of one phase of the AO/AAO over another. This pattern of climate change projects exclusively on the AAO pattern in the southern hemisphere but not in the northern hemisphere where other EOFs are involved. The extent to which this forced climate change pattern and the unforced modes of variation are determined by the same mechanisms and feedbacks remains an open question.