The boreal winter North Pacific Oscillation (NPO) has a significant impact on the tropical Pacific large scale air-sea interaction in the following spring and summer. But it is unclear whether the boreal winter NPO is associated with the El Niño development or decaying during following summer. This study confirms the relationship between the winter NPO-like sea level pressure anomalies and following summertime El Niño and reveals an interdecadal change in this relationship. It tends to promote the development of sea surface temperature anomaly in central equatorial Pacific in the following summer when the subtropical lobe of the NPO located west of its average position. But after a significant eastward shift of NPO’s subtropical lobe, it is more conducive to the development of sea surface temperature anomaly in eastern equatorial Pacific. The eastward shift of the NPO’s subtropical lobe altered both the seasonal foortprint mechanism and the trade wind charging mechanism associated with the NPO, thus profoundly influenced the summertime El Niño. The findings in the present study have implications for a better understanding of the relationship between the boreal winter NPO and the El Niño in developing summer.

北半球冬季北太平洋涛动（NPO）对来年春夏季热带太平洋大规模海气相互作用产生显着影响。但目前还不清楚北半球冬季NPO是否与厄尔尼诺现象的发展或第二年夏季的衰减有关。这项研究证实了冬季类NPO海平面压力异常与夏季厄尔尼诺现象之间的关系，并揭示了这种关系的年代际变化。当NPO副热带叶位于其平均位置以西时，往往会促进次年夏季赤道中太平洋海表温度异常的发展。但NPO副热带叶显着东移后，更有利于赤道东太平洋海温异常的发展。NPO副热带叶瓣东移改变了与NPO相关的季节足迹机制和信风充电机制，从而深刻影响了夏季厄尔尼诺现象。本研究的结果对于更好地理解北方冬季 NPO 与夏季厄尔尼诺现象之间的关系具有重要意义。