NOx (NO2 and NO) plays an important role in controlling stratospheric ozone. Understanding the change in stratospheric NOx and its global pattern is important for predicting future changes in ozone and the corresponding implications on the climate. Stratospheric NOx is mainly produced by the reaction of N2O with the photochemically produced O(1D) and, therefore, it is expected to vary with changes in solar UV irradiance during the solar cycle. Previous studies on this topic, often limited by the relatively short continuous data, show puzzling results. The effect of the 1991 Pinatubo eruption might have caused interference in the data analysis. In this study, we examine the NO2 vertical column density (VCD) data from the Network for the Detection of Atmospheric Composition Change (NDACC). Data collected at 16 stations with continuous long-term observations covering the most recent Solar Cycles 23 and 24 were analyzed. We found positive correlations between changes in NO2 VCD and solar Lyman- $\alpha $ over nine stations (mostly in the Northern Hemisphere) and negative correlations over three stations (mostly in the Southern Hemisphere). The other four stations do not show significant NO2 solar-cycle signal. The varying NO2 responses from one location to another are likely due to different geo-locations (latitude and altitude). In particular, two high-altitude stations show the strongest positive NO2 solar-cycle signals. Our 1D chemical-transport model calculations help explain the altitude dependence of NO2 response to the solar cycle. NO2 solar-cycle variability is suggested to play an important role controlling O3 at an altitude range from $\approx20~\mbox{km}$ to near 60 km, while OH solar-cycle variability controls O3 at 40 – 90 km. While observations show both positive and negative NO2 responses to solar forcing, the 1D model predicts negative NO2 responses to solar UV changes throughout the middle atmosphere. 3D global model results suggest complex roles of dynamics in addition to photochemistry. The energetic particle-induced NO2 variabilities could also contribute significantly to the NO2 variability during solar cycles.

中文翻译：

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平流层二氧化氮中的太阳 11 年周期信号——模型和 NDACC 观测之间的相似性和差异

NOx（NO2和NO）在控制平流层臭氧方面起着重要作用。了解平流层 NOx 的变化及其全球模式对于预测臭氧的未来变化及其对气候的相应影响非常重要。平流层 NOx 主要由 N2O 与光化学产生的 O(1D) 反应产生，因此，预计它会随着太阳周期中太阳紫外线辐照度的变化而变化。以前关于这个主题的研究通常受到相对较短的连续数据的限制，结果令人费解。1991 年皮纳图博火山喷发的影响可能对数据分析造成干扰。在这项研究中，我们检查了来自大气成分变化检测网络 (NDACC) 的 NO2 垂直柱密度 (VCD) 数据。分析了在 16 个站点收集的数据，这些站点具有涵盖最近的太阳周期 23 和 24 的连续长期观测。我们发现 NO2 VCD 的变化与太阳 Lyman-$\alpha $ 的变化在九个站点（主要在北半球）之间呈正相关，在三个站点（主要在南半球）上呈负相关。其他四个站没有显示出明显的 NO2 太阳周期信号。从一个位置到另一个位置不同的 NO2 响应可能是由于不同的地理位置（纬度和高度）。特别是，两个高海拔站显示出最强的正 NO2 太阳周期信号。我们的一维化学传输模型计算有助于解释 NO2 响应对太阳周期的高度依赖性。建议 NO2 太阳周期变率在 $\approx20~\mbox{km}$ 到近 60 公里的高度范围内对控制 O3 发挥重要作用，而 OH 太阳周期变率在 40-90 公里处控制 O3。虽然观察结果显示 NO2 对太阳强迫的积极和消极响应，但一维模型预测 NO2 对整个中间大气层的太阳紫外线变化的负面响应。3D 全局模型结果表明，除了光化学之外，动力学还具有复杂的作用。高能粒子引起的 NO2 变异也可能对太阳循环期间的 NO2 变异产生重大影响。一维模型预测了整个中层大气对太阳紫外线变化的负面 NO2 响应。3D 全局模型结果表明，除了光化学之外，动力学还具有复杂的作用。高能粒子引起的 NO2 变异也可能对太阳循环期间的 NO2 变异产生重大影响。一维模型预测了整个中层大气对太阳紫外线变化的负面 NO2 响应。3D 全局模型结果表明，除了光化学之外，动力学还具有复杂的作用。高能粒子引起的 NO2 变异也可能对太阳循环期间的 NO2 变异产生重大影响。