As the most dominant tropical climate mode on the interannual timescale, El Niño-Southern Oscillation (ENSO) is suggested to significantly influence the interannual variation of East Asian summer monsoon rainfall (EASMRI). However, the leading mode of EASMRI remains almost untouched when the impacts of preceding ENSO events are linearly removed, suggesting the existence of alternative impact factors and predictability sources of EASMRI.

         After removing the impact of ENSO, the sea surface temperature anomalies (SSTAs) over both the tropical Atlantic and extratropical North Atlantic are found to be related with EASMRI via atmospheric teleconnections. Positive SSTA over the tropical Atlantic could induce tropical diabatic heating, which triggers an equivalent barotropic Rossby wave train emitting from the Atlantic, going across the Eurasian continent and ending with a cyclonic anomaly over northeast Asia. The tropical diabatic heating could also induce western North Pacific anomalous anticyclone via a tropical route. The dipole SSTA pattern with cooling in the west and warming in the east over the extratropical North Atlantic induces local circulation anomalies via heat flux exchange, which could further perturb a Rossby wave train with a cyclonic anomaly over northeast Asia, thus modulating EASMRI. Numerical experiments with prescribed atmospheric heating associated with Atlantic SSTAs could realistically reproduce these teleconnections of EASMRI.

          By adding the predictability sources of Atlantic SSTAs, the seasonal prediction skills of EASMRI could be significantly improved over both the tropical western North Pacific and subtropical land regions such as central China and Japan.