During 2013–2020, the northern tropical Pacific Ocean (NTPO, 5° N–20° N) experienced a persistent surface warming of over 0.5 °C. This warming was accompanied by a consecutively low surface chlorophyll (SChl). Here, we combined observations with ocean general circulation model experiments to determine how the interplays between the North Pacific meridional mode (NPMM) and multi-year El Niño events jointly led to this persistent surface warming. The warm phase of NPMM (+) excited an anticyclonic circulation in the NTPO, which caused surface warming and enhanced the upper-ocean stratification in the western sector (160° E–150° W) and also deepened the thermocline in the eastern sector (150° W–110° W), resulting in a widespread decline in SChl. The NPMM (+) also triggered El Niño events during the subsequent winter, further decreasing the negative SChl anomalies by weakening the surface ocean current. Subsequently, two persistent El Niño events happened in succession (2014–2016 and 2018–2020), which acted to accelerate the decline in SChl by 2020. These results help to illustrate the effects of extratropical-tropical interactions on the compound physical-biological extremes under the global warming scenario.

2013年至2020年期间，北热带太平洋（NTPO，5°N–20°N）的表面持续升温超过0.5°C。这种变暖伴随着表面叶绿素（SChl）的持续降低。在这里，我们将观测与海洋环流模型实验相结合，以确定北太平洋经向模式（NPMM）和多年厄尔尼诺事件之间的相互作用如何共同导致这种持续的表面变暖。 NPMM(+)的暖相激发了NTPO的反气旋环流，导致地表变暖，增强了西段(160°E-150°W)的上层海洋层结，也加深了东段的温跃层( 150° W–110° W)，导致 SChl 普遍下降。 NPMM（+）还在随后的冬季引发了厄尔尼诺事件，通过减弱表层洋流进一步减少了 SChl 负异常。随后，两次持续的厄尔尼诺事件（2014-2016年和2018-2020年）连续发生，加速了2020年SChl的下降。这些结果有助于说明温带-热带相互作用对复合物理-生物极端事件的影响。在全球变暖的情况下。