Realistic simulation and accurate prediction of El Niño-Southern Oscillation (ENSO) is still a challenge. One fundamental obstacle is the so-called spring predictability barrier (SPB), which features a low predictive skill of the ENSO with prediction across boreal spring. Our observational analysis shows that the leading empirical orthogonal function mode of the seasonal Niño3.4 index evolution (i.e., from May to the following April) explains nearly 90% of its total variance, and the principle component is almost identical to the Niño3.4 index in the mature phase. This means a good ENSO prediction for a year ranging May-next April can be achieved if the Niño3.4 index in the mature phase is accurately obtained in advance. In this work, by extracting physically oriented variables in the spring, a linear regression approach that can reproduce the mature ENSO phases in observation is firstly proposed. Further investigation indicates that the specific equation, however, is significantly modulated by an interdecadal regime shift in the air–sea coupled system in the tropical Pacific. During 1980–1999, ocean adjustment and vertical processes were dominant, and the recharge oscillator theory was effective to capture the ENSO evolutions. While, during 2000–2018, zonal advection and thermodynamics became important, and successful prediction essentially relies on the wind stress information and their controlled processes, both zonally and meridionally. These results imply that accounting for the interdecadal regime shift of the tropical Pacific coupled system and the dominant processes in spring in modulating the ENSO evolution could reduce the impact of SPB and improve ENSO prediction.

厄尔尼诺-南方涛动（ENSO）的真实模拟和准确预测仍然是一个挑战。一个基本的障碍是所谓的弹簧可预测性障碍（SPB），它的特征是ENSO的预测能力低，无法预测整个北方弹簧。我们的观测分析表明，季节性Niño3.4指数演变的领先经验正交函数模式（即从5月到次年4月）解释了其总方差的近90％，并且主成分与Niño3.4几乎相同指标处于成熟阶段。这意味着，如果提前准确地获得成熟期的Niño3.4指数，则可以对5月至次年4月的一年实现良好的ENSO预测。在这项工作中，通过提取弹簧中的物理定向变量，首先提出了一种线性回归方法，该方法可以再现观测中的成熟ENSO相。进一步的研究表明，该特定方程受热带太平洋海海耦合系统年代际变化的影响很大。在1980-1999年期间，海洋调整和垂直过程占主导地位，补给振荡理论有效地捕获了ENSO的演变。虽然在2000–2018年期间，纬向平流和热力学变得非常重要，但成功的预测基本上取决于纬向和子午的风应力信息及其控制过程。