This paper investigates potential factors that control the El Nino–Southern Oscillation (ENSO) Spring Persistence Barrier (SPB) strength in two different ENSO regimes and apply it to explain the ENSO SPB strength modulation after the 21st century. In a damped, noise-driven model, the theoretical solution of SPB strength illustrates that a weaker ENSO growth rate strengthens SPB. In the self-sustained regime, as in the Cane-Zebiak model (chaotic system), the strengthened thermodynamic damping and weakened thermocline positive feedback lead to a more negative ENSO growth rate and, in turn, a stronger SPB. Therefore, in both ENSO regimes, a weaker ENSO growth rate intensifies the SPB. The application of the theory to the real world suggests that a more negative ENSO growth rate, corresponding to a more damped feedback system, is responsible for the stronger SPB in recent decades than in 1980–2000. (Less)

中文翻译：

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不同 ENSO 体制下弹簧持久性屏障强度的控制及其对二十世纪变化的影响

本文研究了在两种不同的 ENSO 状态下控制厄尔尼诺-南方涛动 (ENSO) 弹簧持久势垒 (SPB) 强度的潜在因素，并将其应用于解释 21 世纪之后的 ENSO SPB 强度调制。在阻尼、噪声驱动的模型中，SPB 强度的理论解表明，较弱的 ENSO 增长率会增强 SPB。在自持状态下，如在 Cane-Zebiak 模型（混沌系统）中，增强的热力学阻尼和减弱的温跃层正反馈导致更负的 ENSO 增长率，进而导致更强的 SPB。因此，在两种 ENSO 机制中，较弱的 ENSO 增长率会加剧 SPB。该理论在现实世界中的应用表明，更负的 ENSO 增长率，对应于更阻尼的反馈系统，是近几十年来 SPB 比 1980-2000 年更强的原因。（较少的）