Effect of the air-sea coupled system change on the ENSO evolution from boreal spring
Effect of the air-sea coupled system change on the ENSO evolution from boreal spring
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海气耦合系统变化对北泉ENSO演变的影响
DOI：
10.1007/s00382-021-05697-w
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发表时间：
2021
期刊：
影响因子：
4.6
通讯作者：
Zheng Fei
中科院分区：
文献类型：
--
作者：
Fang Xiang-Hui;Zheng Fei
对厄尔尼诺-南方涛动（ENSO）的现实模拟和准确预测仍然是一个挑战。一个根本的障碍是所谓的春季可预测性障碍（SPB），其特点是ENSO的预测能力较低，预测整个北方春季。我们的观测分析表明，季节性Niño3.4指数演变的主要经验正交函数模式（即，从5月到次年4月）解释了其总方差的近90%，主成分与成熟期的Niño3.4指数几乎一致。这意味着如果提前准确地获得成熟阶段的Niño3.4指数，就可以对5-次年4月的ENSO做出较好的预报。本文首次提出了一种通过提取春季物理量的线性回归方法来重现ENSO成熟位相。然而，进一步的研究表明，热带太平洋海气耦合系统的年代际体制转换显著调制了特定的方程。在1980-1999年期间，海洋调整和垂直过程占主导地位，补给振荡器理论是有效的捕捉ENSO演变。然而，在2000-2018年期间，纬向平流和热力学变得重要，成功的预测基本上依赖于风应力信息及其控制过程，无论是纬向还是纬向。这些结果表明，考虑热带太平洋耦合系统的年代际体制转换和春季主导过程对ENSO演变的影响，可以减少SPB的影响，提高ENSO的预报水平。
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.