Ozone in the upper troposphere–lower stratosphere (UTLS) is primarily regulated by tropospheric dynamics. Understanding mechanisms driving ozone variability at the UTLS is crucial to evaluate the transport of mass to and from the lower stratosphere. The El Niño-Southern Oscillation (ENSO) is the primary coupled mode acting on interannual timescales modulating tropospheric circulation worldwide. ENSO teleconnections can depend on the phases of the Pacific Decadal Oscillation (PDO) and on the characteristics of the warming over central and eastern tropical Pacific. This study investigates the role of ENSO on UTLS ozone variability with focus on South America and examines patterns of teleconnections in the two recent warm (1980–1997) and cool (1998–2012) PDO phases. The dominant mode of ozone variability is identified by applying a principal component analysis (PCA) to modern-era retrospective analysis for research and applications, Version 2 (MERRA-2) ozone data from September–November (SON). SON is the season with the largest UTLS ozone variance over South America. The first mode resembles a Rossby wave train across South America with spatial patterns dependent on PDO phase. We show that the ENSO teleconnections and respective influences on SON UTLS ozone are stronger during the cool PDO when ENSO and PDO are mostly in phase. Additionally, the strength of the ENSO teleconnection appears to depend on patterns of SST anomalies over tropical Pacific. The decadal variability in the ENSO-PDO relationships and teleconnections with the Southern Hemisphere resulted in a shift in upper tropospheric circulation in tropical and subtropical regions of South America.

对流层-平流层下部的臭氧主要受对流层动力学的调节。了解在UTLS处驱动臭氧变化的机制对于评估低空平流层之间的物质传输至关重要。厄尔尼诺-南方涛动（ENSO）是主要的耦合模式，作用于调节全球对流层环流的年际时标。ENSO的远距连接可能取决于太平洋年代际振荡（PDO）的阶段以及中部和东部热带太平洋变暖的特征。这项研究主要针对南美地区，研究了ENSO在UTLS臭氧变率中的作用，并研究了最近两个PDO暖期（1980-1997）和凉爽（1998-2012）阶段的遥相关模式。臭氧变率的主要模式是通过将主成分分析（PCA）应用于研究和应用的现代追溯分析，即9月至11月（SON）的第2版（MERRA-2）臭氧数据而确定的。SON是整个南美地区UTLS臭氧变化最大的季节。第一种模式类似于横跨南美的Rossby波列，其空间模式取决于PDO相位。我们表明，在ENSO和PDO大多处于同相状态的凉爽PDO期间，ENSO遥相关以及对SON UTLS臭氧的影响更强。此外，ENSO远程连接的强度似乎取决于热带太平洋上SST异常的模式。