UC Irvine

To understand the unique temporal evolution of the 2014–2016 multiyear El Niño event, which can be characterized as a successive and reintensified event preceded by a weak El Niño, this study examines similar events in a 2,200-yr simulation of Community Earth System Model, version 1. By contrasting multiyear El Niño events with single-year ones, we find that the succession characteristics of multiyear El Niño events are primarily caused by a negative North Pacific Oscillation (NPO) in the first-year winter via subtropical Pacific coupling processes. By contrasting reintensified multiyear El Niño events with lingering ones, we find that the reintensification characteristics are caused by a negative Indian Ocean Dipole (IOD) in the first-year fall via tropical interbasin coupling processes. The phase information of the preceding winter NPO and fall IOD together can be used to project the evolution characteristics of El Niño events, particularly the reintensified multiyear and transitional single-year events.