Premium
Multidecadal fluctuations in the relationship between equatorial Pacific heat content anomalies and ENSO amplitude
Author(s) -
Cai Wenju,
McPhaden Michael J.,
Collier Mark A.
Publication year - 2004
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 - 10.1029/2003gl018714
Subject(s) - anomaly (physics) , sea surface temperature , upwelling , climatology , el niño southern oscillation , asymmetry , amplitude , ocean heat content , pacific decadal oscillation , magnitude (astronomy) , environmental science , geology , forcing (mathematics) , oceanography , physics , quantum mechanics , condensed matter physics , astronomy
Observations over the past 20 years indicate that equatorial Pacific Ocean heat content variations associated with El Niño‐Southern Oscillation (ENSO) cycles lead sea surface temperature (SST) anomalies in the equatorial cold tongue by about 7 months. However, an asymmetry exists in the relationship between SST and heat content: positive SST anomalies related to El Niño are stronger than negative SST anomalies related to La Niña for the same magnitude (but opposite sign) heat content anomaly. In this study, we analyse a multi‐century simulation using the CSIRO Mark 3 coupled climate model to show that a similar asymmetry exists in some decades but not in others. This non‐stationarity appears to be a consequence of modulations by a mode of multidecadal variability which affects the temperature of upwelled water and the efficiency with which upwelling generates SST anomalies.