Understanding the Interdecadal Changes in the Teleconnection Pattern of the East Asian Summer Monsoon Precipitation With Concurrent ENSO

Abstract

Interdecadal changes in the relationship between East Asian Summer Monsoon Precipitation (EASMP) and the concurrent El Niño-Southern Oscillation (ENSO) vary across subregions, making it challenging to holistically understand these variations and the underlying mechanisms. To address this issue, we apply the moving correlation Empirical Orthogonal Function (MC-EOF) between EASMP and ENSO, identifying a meridional tri-pole pattern in the interdecadal variation of their relationship. The primary driver of this pattern is the summer Tropical North Atlantic (TNA) sea surface temperature, which has shifted from being uncorrelated to exhibiting a strong negative correlation with concurrent ENSO since the late 1980s. Consequently, the TNA's influence on EASMP combines with ENSO's effects, altering the EASMP pattern during ENSO events. This conclusion is supported by two observations: (a) the moving correlation series between TNA and ENSO aligns with the time series of MC-EOF-1, and (b) the MC-EOF-1 pattern spatially matches the TNA's impact on EASMP.