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.

中文翻译：

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了解东亚夏季季风降水与并发 ENSO 遥相关模式的年代际变化


东亚夏季季风降水 （EASMP） 与同时发生的厄尔尼诺-南方涛动 （ENSO） 之间关系的年代际变化因子区域而异，因此很难全面理解这些变化和潜在机制。为了解决这个问题，我们在 EASMP 和 ENSO 之间应用了移动相关经验正交函数 （MC-EOF），确定了它们关系的年代际变化中的经向三极模式。这种模式的主要驱动因素是夏季热带北大西洋 （TNA） 海面温度，自 1980 年代后期以来，该温度已从不相关转变为与同时发生的 ENSO 呈强负相关。因此，TNA 对 EASMP 的影响与 ENSO 的影响相结合，在 ENSO 事件期间改变了 EASMP 模式。这一结论得到了两个观察结果的支持：（a） TNA 和 ENSO 之间的移动相关序列与 MC-EOF-1 的时间序列一致，以及 （b） MC-EOF-1 模式在空间上与 TNA 对 EASMP 的影响相匹配。