The ENSO and its modulation in a coupled GCM
Yoshiteru Kitamura
meteorological Research Institute /JMA
A 200 years integration of a coupled GCM with flux correction was made. Dominated interannual variation is an ENSO-like variation over the tropical Pacific with 2 to 4 years period. The SST increase (decrease) over the central to eastern equatorial Pacific accompanies the weakening (strengthening) of the Walker circulation and of the thermocline zonal gradient. Corresponding changes over the Indian Ocean including Indian Monsoon are seen. The SST change along the equatorial Pacific is generally stationary, while the eastward propagation of the ocean heat content is apparent. Intensity of the ENSO, particularly that of the El Nino, are found to vary with decadal timescale. The strong El Nino tends to occur when the zonally integrated ocean heat content within the equatorial band is small. The associated meridional heat exchange between the equatorial Pacific and the subtropical north Pacific is investigated.
