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Migration of atmospheric convection coupled with ocean currents pushes El Niño to extremes
Author(s) -
Kim WonMoo,
Cai Wenju,
Kug JongSeong
Publication year - 2015
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 - 10.1002/2015gl063886
Subject(s) - advection , convection , geology , climatology , atmospheric convection , amplitude , atmospheric sciences , mechanics , troposphere , physics , quantum mechanics , thermodynamics
The warm phase of El Niño–Southern Oscillation can grow much stronger than the cold phase, but the associated dynamics are not well understood. Here we show that the anomalous zonal advection of warm water is the major process that pushes El Niño to extremes and that this anomalous advection results from the coupling of oceanic currents with eastward migration of the atmospheric convection; a greater zonal advection is associated with a greater extent of the eastward migration. By contrast, there is a limited extent for westward migration during La Niña. Climate models that successfully simulate the amplitude asymmetry display a systematic linkage of a greater longitudinal movement of the convection center with a stronger zonal advection and greater El Niño amplitude. In a warming world, the longitudinal migration of convection response increases, as does the role of zonal advection, increasing the frequency of future extremes of El Niño.