The North Pacific Oscillation (NPO), an important mode of atmospheric variability, is a crucial trigger for the development of El Niño-Southern Oscillation (ENSO) via the seasonal footprinting mechanism. How the NPO effect on ENSO changes in response to greenhouse warming remains unclear, however. Here, using climate model simulations under high-emission scenarios, we show that greenhouse warming leads to an enhanced influence of NPO on ENSO as is manifested by enhanced responses of winter sea surface temperature (SST), precipitation and wind anomalies in the equatorial Pacific to the preceding winter NPO. The strengthened NPO impact is also reflected in an increased frequency of NPO events that are followed by ENSO events. Warmer background SST enhances the wind-evaporation-SST feedback over the subtropical North Pacific due to a nonlinear SST-evaporation relationship. This strengthens the NPO-generated surface zonal wind anomalies over the equatorial western-central Pacific, which trigger ENSO. Increased impact of winter NPO on ENSO could enable prediction of interannual variability at longer leads.

北太平洋涛动（NPO）是一种重要的大气变化模式，通过季节足迹机制是厄尔尼诺-南方涛动（ENSO）发展的关键触发因素。然而，NPO 对 ENSO 的影响如何因温室变暖而变化仍不清楚。在这里，我们利用高排放情景下的气候模型模拟，表明温室变暖导致NPO对ENSO的影响增强，表现为赤道太平洋冬季海面温度（SST）、降水和风异常对ENSO的响应增强。之前的冬季 NPO。NPO 影响的增强还体现在 NPO 事件发生频率增加，随后发生 ENSO 事件。由于非线性海温-蒸发关系，较温暖的背景海温增强了副热带北太平洋的风-蒸发-海温反馈。这加强了 NPO 产生的赤道中西太平洋表面纬向风异常，从而引发 ENSO。冬季 NPO 对 ENSO 影响的增加可以预测较长提前期的年际变化。