Driving mechanisms for the El Niño–Southern Oscillation impact on stratospheric ozone
Driving mechanisms for the El Niño–Southern Oscillation impact on stratospheric ozone
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DOI：
10.5194/acp-22-15729-2022
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发表时间：
2022-12
影响因子：
6.3
通讯作者：
Samuel Benito-Barca;N. Calvo;M. Abalos
中科院分区：
文献类型：
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作者：
Samuel Benito-Barca;N. Calvo;M. Abalos
抽象。虽然人们早就认识到厄尔尼诺-南方涛动对平流层环流的影响，但对其对平流层臭氧的影响的研究较少。特别是，不同的ENSO风味，东太平洋（EP）厄尔尼诺和中太平洋（CP）厄尔尼诺对臭氧的影响，以及臭氧变化的驱动机制迄今尚未研究。本研究旨在探讨这些开放性问题，通过检查异常平流输送，混合和化学与不同的厄尔尼诺风味（EP和CP）和拉尼娜在北方半球在北方冬季。为此，我们使用了全大气共同体气候模式第4版的四个60年集合成员。结果表明，在EP厄尔尼诺和拉尼娜事件期间，总柱臭氧（TCO）上存在显著的ENSO信号。在EP厄尔尼诺事件期间，热带地区的总拥有量显着减少，而北方冬季中高纬度地区的总拥有量则增加。在拉尼娜现象期间，人们发现了相反的反应。有趣的是，CP厄尔尼诺对热带外TCO没有显著影响，而其在热带的信号比EP厄尔尼诺事件弱。对机制的分析表明，通过热带上升流变化产生的平流是热带平流层下部臭氧变化的主要驱动力，30百帕以上的化学过程也起了作用。在中高纬度地区，与厄尔尼诺/南方涛动有关的平流层臭氧变化是由剩余环流下降流引起的平流变化和与Rossby波破碎和极涡异常有关的水平混合变化共同造成的。CP厄尔尼诺对剩余环流的浅分支影响较小，对深分支影响不显著。
Abstract. While the impact of the El Niño–Southern Oscillation (ENSO) on the stratospheric circulation has been long recognized, its effects on stratospheric ozone have been less investigated. In particular, the impact on ozone of different ENSO flavors, eastern Pacific (EP) El Niño and central Pacific (CP) El Niño, and the driving mechanisms for the ozone variations have not been investigated to date. This study aims to explore these open questions by examining the anomalies in advective transport, mixing and chemistry associated with different El Niño flavors (EP and CP) and La Niña in the Northern Hemisphere in boreal winter. For this purpose, we use four 60-year ensemble members of the Whole Atmospheric Community Climate Model version 4. The results show a significant ENSO signal on the total column ozone (TCO) during EP El Niño and La Niña events. During EP El Niño events, TCO is significantly reduced in the tropics and enhanced at middle and high latitudes in boreal winter. The opposite response has been found during La Niña. Interestingly, CP El Niño has no significant impact on extratropical TCO, while its signal in the tropics is weaker than for EP El Niño events. The analysis of mechanisms reveals that advection through changes in tropical upwelling is the main driver for ozone variations in the lower tropical stratosphere, with a contribution of chemical processes above 30 hPa. At middle and high latitudes, stratospheric ozone variations related to ENSO result from combined changes in advection by residual circulation downwelling and changes in horizontal mixing linked to Rossby wave breaking and polar vortex anomalies. The impact of CP El Niño on the shallow branch of the residual circulation is small, and no significant impact is found on the deep branch.