| coupled ocean and atmosphere model was built and used to test a proposed mechanism about the timing structure of the El Nino/Southern Oscillation (ENSO) signal. The coupled model successfully simulated the timing structure as found in the observations. Specifically, the time interval ;The modeled ENSO events are well described by the delayed oscillator mechanism. The mechanism involves a coupled ocean-atmosphere instability and a delayed negative feedback. During instability growth, the sea surface temperature anomaly in the central Pacific is primarily generated by advection due to anomalous currents. The reflected Kelvin wave from the western boundary is crucial to the negative feedback.;Simulations from the coupled model confirmed the proposed physics for the timing of ENSO. When the warm event is larger the anomalous westerly winds in the coupled ocean-atmosphere instability are further from the western ocean boundary. The westerlies generate Rossby waves which propagate westward and reflect from the western boundary as eastward-propagating equatorial Kelvin waves which trigger the negative coupled ocean-atmosphere feedback. The time interval... |
