Two atmospheric feedbacks play an important role in the dynamics of the El Niño/Southern Oscillation (ENSO), namely the amplifying zonal wind feedback and the damping heat flux feedback. Here we investigate how and why both feedbacks change under global warming in climate models participating in the 5th and 6th phase of the Coupled Model Intercomparison Project (CMIP5 and CMIP6) under the business-as-usual scenario (RCP8.5 and SSP5-8.5, respectively). The amplifying zonal wind feedback over the western equatorial Pacific (WEP) becomes significantly stronger in two third of the models, on average by 12 ± 7% in these models. The heat flux damping feedback over the eastern and central equatorial Pacific (EEP and CEP, respectively) increases as well in nearly all models, with the damping effect increasing on average by 18 ± 11%. The simultaneous strengthening of the two feedbacks can be explained by the stronger warming in the EEP relative to the WEP and the off-equatorial regions, which shifts the rising branch of the Pacific Walker Circulation to the east and increases the mean convection over the CEP. This in turn leads to a stronger vertical wind response during ENSO events over the CEP that strengthens both atmospheric feedbacks. We separate the climate models into sub-ensembles with STRONG and WEAK ENSO atmospheric feedbacks, as 2/3 of the models underestimate both feedbacks under present-day conditions by more than 40%, causing an error compensation in the ENSO dynamics. The biased mean state in WEAK in 20C constrains the ENSO atmospheric feedback projection in 21C, as the models of the WEAK sub-ensemble also have weaker ENSO atmospheric feedbacks in 21C. Further, due to the more realistic dynamics and teleconnections, we postulate that one should have more confidence in the ENSO predictions with models belonging to the STRONG sub-ensemble. Finally, we analyze the relation between ENSO amplitude change and ENSO atmospheric feedback change. We find that models simulating an eastward shift of the zonal wind feedback and increasing precipitation over the EEP during Eastern Pacific El Niño events tend to predict a larger ENSO amplitude in response to global warming.

两种大气反馈在厄尔尼诺/南方涛动 (ENSO) 的动力学中起着重要作用，即放大纬向风反馈和阻尼热通量反馈。在这里，我们研究了在一切照旧情景（RCP8.5 和 SSP5-8.5，RCP8.5 和 SSP5-8.5，分别）。在三分之二的模型中，赤道西部太平洋 (WEP) 上的放大纬向风反馈明显增强，在这些模型中平均增强 12 ± 7%。在几乎所有模型中，赤道东部和中部太平洋（分别为 EEP 和 CEP）的热通量阻尼反馈也增加，阻尼效应平均增加 18 ± 11%。这两个反馈的同时加强可以解释为 EEP 相对于 WEP 和非赤道地区变暖更强，这将太平洋沃克环流的上升分支向东移动并增加了 CEP 上的平均对流。这反过来导致 CEP 上的 ENSO 事件期间更强的垂直风响应，从而加强了大气反馈。我们将气候模型分成具有强和弱 ENSO 大气反馈的子集合，因为 2/3 的模型在当前条件下低估了这两种反馈超过 40%，导致 ENSO 动力学中的误差补偿。20C 的 WEAK 中有偏差的平均状态限制了 21C 的 ENSO 大气反馈预测，因为 WEAK 子集合的模型在 21C 也有较弱的 ENSO 大气反馈。更远，由于更现实的动力学和遥相关，我们假设人们应该对属于 STRONG 子集合的模型的 ENSO 预测更有信心。最后分析了ENSO振幅变化与ENSO大气反馈变化的关系。我们发现模拟东太平洋厄尔尼诺事件期间纬向风反馈向东移动和 EEP 降水增加的模型倾向于预测更大的 ENSO 振幅以响应全球变暖。