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Variation of mean sea surface temperature and modulation of El Niño–Southern Oscillation variance during the past 150 years
Author(s) -
Fang Yue,
Chiang John C. H.,
Chang Ping
Publication year - 2008
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 - 10.1029/2008gl033761
Subject(s) - climatology , sea surface temperature , el niño southern oscillation , entrainment (biomusicology) , southern hemisphere , northern hemisphere , environmental science , mode (computer interface) , southern oscillation , pacific decadal oscillation , multivariate enso index , atmospheric sciences , geology , rhythm , physics , acoustics , computer science , operating system
Evidence is presented that the dominant non‐trend mode of interdecadal global SST variations is linked to significant modulation of ENSO variance during the past 150 years. The mode resembles the interhemispheric SST pattern linked to Sahel rainfall changes, with colder northern hemisphere conditions co‐incident with higher ENSO variance. Simulations of an intermediate coupled global climate model demonstrate that this global SST pattern can drive the interdecadal changes to ENSO variance. The influence on the ENSO dynamics comes primarily from the portion of the SST change local to the tropical Pacific, which is warm over the entire equatorial Pacific particularly in the southeast during times of stronger ENSO activity. We speculate that the warming equatorial SST causes ENSO events occur earlier and thus have longer time to develop, as well as enhancing the vertical temperature gradient and thus increasing the effectiveness of oceanic entrainment.