据了解，厄尔尼诺-南方涛动（ENSO）起源于赤道太平洋中部和东部，是年际气候变率的决定性模式，对全球气候和生态系统产生了深远影响。然而，人们对ENSO如何在地质时间尺度上演变的理解仍然缺乏，尽管普遍的理解认为其对限制人类引起的未来ENSO变化具有直接意义。
通过气候模拟，该研究组发现ENSO在过去250年中一直是热带海表温度（SST）变率的主要模式，但在各个地质时期的幅度变化很大。研究人员通过执行和分析一系列耦合的时间片气候模拟来证明这一结果，这些模拟是由古地理、大气二氧化碳浓度和太阳辐射，在过去250万年中以10万年为间隔进行的。根据线性稳定性分析，ENSO振幅在不同地质时期的变化，与赤道纬向平均海温梯度或各自时期的全球平均地表温度关系不大，而主要由背景温跃层深度的周期间差异决定。
此外，大气噪声的变化是ENSO在不同地质时期变化的一个独立因素。这两个因素共同解释了过去250年来ENSO振幅周期间变化的76%。研究结果强调，该发现支持了海洋垂直热结构变化和大气噪声，在影响预测的未来ENSO变化及其不确定性方面的重要性。
附：英文原文
Title: Persistently active El Niño–Southern Oscillation since the Mesozoic
Author: Li, Xiang, Hu, Shineng, Hu, Yongyun, Cai, Wenju, Jin, Yishuai, Lu, Zhengyao, Guo, Jiaqi, Lan, Jiawenjing, Lin, Qifan, Yuan, Shuai, Zhang, Jian, Wei, Qiang, Liu, Yonggang, Yang, Jun, Nie, Ji
Issue&Volume: 2024-10-21
Abstract: The El Nio–Southern Oscillation (ENSO), originating in the central and eastern equatorial Pacific, is a defining mode of interannual climate variability with profound impact on global climate and ecosystems. However, an understanding of how the ENSO might have evolved over geological timescales is still lacking, despite a well-accepted recognition that such an understanding has direct implications for constraining human-induced future ENSO changes. Here, using climate simulations, we show that ENSO has been a leading mode of tropical sea surface temperature (SST) variability in the past 250 My but with substantial variations in amplitude across geological periods. We show this result by performing and analyzing a series of coupled time-slice climate simulations forced by paleogeography, atmospheric CO2 concentrations, and solar radiation for the past 250 My, in 10-My intervals. The variations in ENSO amplitude across geological periods are little related to mean equatorial zonal SST gradient or global mean surface temperature of the respective periods but are primarily determined by interperiod difference in the background thermocline depth, according to a linear stability analysis. In addition, variations in atmospheric noise serve as an independent contributing factor to ENSO variations across intergeological periods. The two factors together explain about 76% of the interperiod variations in ENSO amplitude over the past 250 My. Our findings support the importance of changing ocean vertical thermal structure and atmospheric noise in influencing projected future ENSO change and its uncertainty.
DOI: 10.1073/pnas.2404758121
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2404758121