Two regimes of inter-basin interactions between the Atlantic and Pacific Oceans on interannual timescales

Abstract Understanding the inter-basin interactions between Atlantic and Pacific Oceans is of great concern due to their substantial global climatic implications. By analyzing observational reanalysis datasets (1948–2020), we found that there are two regimes in Atlantic–Pacific interactions: (1) Pacific-driven regime, (2) Atlantic-driven regime. In regime before mid-1980s, El Niño–Southern Oscillation (ENSO) winter effectively drives primary mode sea surface temperature anomaly (SSTA) tropical (i.e., North Tropical (NTA) mode) following spring. The NTA has a meridional contrast SSTA along Intertropical Convergence Zone, similar Meridional Mode. Whereas, after ENSO effect on becomes remarkably weaker, so featured with monopole. Notably, without capable modulating an event lag. Our analyses latest climate models participating Coupled Model Intercomparison Project (CMIP) phases 6 support hypothesis engendered by likely natural variability.