Distinct pantropical climate interactions modulate the decay pace of Central Pacific El Niño events

The decay pace of Central Pacific (CP) El Niño events, a critical factor influencing global climate patterns and seasonal predictability, has remained poorly understood and difficult to forecast. This study demonstrates that the decay pace of CP El Niño is governed by competing pantropical interactions. Analyses of observational data and Community Earth System Model version 1 simulations reveal two distinct evolutionary pathways. Fast-decaying events are characterized by strong inter-basin teleconnections, wherein strong developing intensity triggers negative feedbacks from the Indian and Atlantic Oceans that drive rapid termination. In contrast, slow-decaying events are maintained through intra-basin processes, whereby CP El Niño effectively interacts with a positive North Pacific Meridional Mode that sustains warming via coupled ocean–atmosphere feedbacks. Developing Niño3.4 intensity (inter-basin termination) and peak-winter subtropical northeastern Pacific variability (intra-basin persistence) are statistically independent, enabling skillful seasonal predictions. Our empirical model achieves high accuracy in both observations and simulations, validating the dual-pathway framework. While confirming the role of tropical–subtropical interaction in sustaining CP El Niño, we show that decay pathways are determined earlier during summer development by initial intensity differences—not peak winter strength as previously thought. These findings resolve the CP El Niño decay paradox through competing remote termination and local persistence mechanisms. Our dual-pathway framework and empirical model therefore provide a crucial mechanistic basis for improving predictions of how El Niño will evolve under global warming. 中部型厄尔尼诺(CP El Niño)的衰减速度是全球气候预测的关键, 但其机制尚不明确.本文揭示其衰减受跨海盆与海盆内相互作用的竞争调控, 存在两种路径:快速发展型事件因发展期强度大, 激发印度洋和大西洋的负反馈而快速终止;缓慢衰减型则通过激发北太平洋经向模态, 经海气耦合正反馈得以维持.基于发展期Niño3.4海温和峰值期副热带东北太平洋海温这两个独立因子构建的预测模型在观测与模拟中表现良好, 验证了双路径衰减机制.