The El Niño-Southern Oscillation (ENSO), a dominant driver of interannual climate variations around the world, is characterized in the central-to-eastern tropical Pacific by anomalous sea-surface warming during the El Niño phase and cooling during the La Niña phase. Although ENSO strongly affects atmospheric circulation in East Asia, its effects on tropospheric ozone there have not been fully explored. Here we use satellite measurements of tropospheric column ozone and chemistry-climate model simulations to assess the effects of atmospheric circulations driven by ENSO on tropospheric column ozone levels in East Asia. We find that the observed ozone tends to increase in the East Asian troposphere 4 months after the La Niña peak, corresponding to anomalous northerly downward motions and suppressed convection. The circulation changes can be attributed to anomalous cyclonic flows in the western North Pacific, which links the La Niña and East Asian climate by modulating meridional transport of water vapor. These post-La Niña changes are also evident in the chemistry-climate model results, albeit with a slightly longer (5-month) lag. The model also reveals that La Niña-related ozone enhancement in East Asia is largely due to the intensified southward transport of ozone-rich air from higher latitudes. This suggests that ENSO should be considered to estimate the ozone concentration in East Asia, requiring much attention of ENSO properties in a changing climate.

厄尔尼诺-南方涛动 (ENSO) 是世界各地年际气候变化的主要驱动因素，其特征是中东部热带太平洋在厄尔尼诺阶段海面异常变暖和拉尼娜阶段变冷. 尽管 ENSO 对东亚大气环流有强烈影响，但其对东亚对流层臭氧的影响尚未得到充分探讨。在这里，我们使用对流层臭氧的卫星测量和化学气候模型模拟来评估由 ENSO 驱动的大气环流对东亚对流层臭氧水平的影响。我们发现，在拉尼娜峰值后 4 个月，东亚对流层观测到的臭氧趋于增加，对应于异常的北下向下运动和对流的抑制。环流变化可归因于北太平洋西部的异常气旋流，它通过调节水汽的经向传输将拉尼娜和东亚气候联系起来。这些后拉尼娜现象在化学-气候模型结果中也很明显，尽管滞后时间稍长（5 个月）。该模型还表明，东亚与拉尼娜现象相关的臭氧增强主要是由于来自高纬度地区的富含臭氧的空气向南迁移的加剧。这表明应该考虑使用 ENSO 来估计东亚的臭氧浓度，这需要在气候变化中非常关注 ENSO 的特性。这些后拉尼娜现象在化学-气候模型结果中也很明显，尽管滞后时间稍长（5 个月）。该模型还表明，东亚与拉尼娜现象相关的臭氧增强主要是由于来自高纬度地区的富含臭氧的空气向南迁移的加剧。这表明应该考虑使用 ENSO 来估计东亚的臭氧浓度，这需要在气候变化中非常关注 ENSO 的特性。这些后拉尼娜现象在化学-气候模型结果中也很明显，尽管滞后时间稍长（5 个月）。该模型还表明，东亚与拉尼娜现象相关的臭氧增强主要是由于来自高纬度地区的富含臭氧的空气向南迁移的加剧。这表明应该考虑使用 ENSO 来估计东亚的臭氧浓度，这需要在气候变化中非常关注 ENSO 的特性。