ENSO Diversity Explains Interannual Variability of the Pattern Effect

Abstract The spatial pattern of sea surface temperature (SST) affects the global radiative budget through the “pattern effect.” While previous studies highlighted the role of El Niño–Southern Oscillation (ENSO) in unforced pattern effect, a systematic assessment of the dominant modes of SST variability for the top of atmosphere energy budget has been lacking. Using Partial Least Squares Regression, we identify Eastern Pacific and Modoki ENSO as the two leading modes most relevant to the pattern effect at interannual timescales. These ENSO variants exhibit distinct radiative signatures due to subtle shifts in the location of SST anomalies relative to the climatological warm pool. Furthermore, analysis of individual ENSO events indicates that each event has a unique radiative signature depending on its evolving spatial structure. These findings highlight the importance of accounting for ENSO diversity to accurately understand how modes of SST variability influence the global energy budget.