Part II model support on a new mechanism for North Pacific Oscillation influence on ENSO

Abstract Owing to the significant influence of El Niño-Southern Oscillation (ENSO) on global climate, how ENSO events are initiated is an intriguing issue. The North Pacific (NPO), a primary atmospheric variability over midlatitude, well-known trigger for events, but physical linkage not yet fully understood. Based observational analyses, in Part I, we proposed new mechanism that NPO-related wave activity flux (WAF) could directly induce equatorial wind anomalies both upper and lower levels. In this study, substantiate impacts WAF tropical circulations using climate models participating Coupled Model Intercomparison Project phases 5 6 (CMIP5/6). We found intensity southward central paramount factor resulting intermodel diversity simulating NPO–ENSO linkage. By classifying into two groups strong weak meridional (MWAF), reveal MWAF simulate stronger upper- lower-level winds precipitation facilitate subsequent winter. also magnitude closely related model’s climatological shear zonal wind, emphasizing role systematic bias simulation. A comparison impact seasonal footprinting demonstrates dominant determining relationships.