A lagged warm event-like response to peaks in solar forcing in the Pacific region

The forced response coincident with peaks in the 11-yr decadal solar oscillation (DSO) has been shown to resemble a cold event or La Niña-like pattern during December-February (DJF) in the Pacific region in observations and two global coupled climate models. Previous studies with filtered observational and model data have indicated that there could be a lagged warm event or El Niño-like response following the peaks in the DSO forcing by a few years. Here, observations and two climate model simulations are examined, and it is shown that dynamical coupled processes initiated by the response in the tropical Pacific to peaks in solar forcing produce wind-forced ocean Rossby waves near 5°N and 5°S. These reflect off the western boundary, producing downwelling equatorial Kelvin waves that contribute to transitioning the tropical Pacific to a warm event or El Niño-like pattern that lags the peaks in solar forcing by a few years.