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Interdecadal variability of the ENSO–North Atlantic Oscillation connection in boreal summer
Author(s) -
Wu Zhiwei,
Lin Hai
Publication year - 2012
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.1889
Subject(s) - extratropical cyclone , climatology , rossby wave , north atlantic oscillation , boreal , environmental science , anomaly (physics) , sea surface temperature , el niño southern oscillation , atlantic multidecadal oscillation , pacific decadal oscillation , southern oscillation , geology , oceanography , physics , paleontology , condensed matter physics
Understanding the combined effect of El Niño–Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) is of great importance for climate seasonal prediction (extreme climate events in particular). Results in this study show that during the last hundred years (1900 to present), the ENSO–NAO connection experiences a notable interdecadal change in summer (June–August) according to a 21‐year sliding correlation between them, namely, from no significant correlation (uncoupling) before the mid‐1970s to a significant correlation (coupling) after the mid‐1970s. Comparison analysis between the coupling epoch (1977–1997) and the uncoupling epoch (1958–1976) shows that the most pronounced circulation anomalies take place over the extratropical North Pacific. Further analysis and numerical experiments suggest that a poleward‐propagating Rossby wave train, possibly enhanced by sea‐surface‐temperature anomalies in the extratropical North Pacific associated with the developing phases of ENSO during the later epoch, is responsible for connecting the ENSO signal with the NAO. © 2012 Crown in the right of Canada. Published by JohnWiley & Sons Ltd.