Disruption of the ENSO–tropical cyclone relationship in the western North Pacific during successive ENSO events

The canonical relationship between the El Niño-Southern Oscillation (ENSO) and tropical cyclone (TC) activity in the western North Pacific (WNP) is well established, yet its stability across different ENSO temporal evolutions remains unclear. Using ERA5 reanalysis datasets, ERSSTv5, IBTrACS TC records (1965–2023), and the Dynamic Genesis Potential Index (DGPI), we demonstrate that this relationship substantially weakens during successive ENSO events. While Reversal ENSO events trigger coherent basin-wide cyclonic anomalies and significantly elevate JAS ACE, Isolated events produce a weaker but still positive TC response, successive events induce a unique cyclone–anticyclone dipole over the WNP. This dipole structure exerts opposing dynamical influences that effectively cancel each other out within the primary TC genesis region, resulting in a non-significant ACE response. Factor decomposition of the DGPI reveals that this cancellation is primarily driven by the competition between suppressed low-level vorticity and enhanced mid-tropospheric ascending motion. High-resolution climate projections from CMIP6/HighResMIP suggest a ∼30% increase in the frequency of successive ENSO events under future warming scenarios. Our findings imply that the increasing prevalence of Successive ENSO will reduce the seasonal predictability of WNP TCs, necessitating the integration of ENSO temporal typology into operational forecasting frameworks.