Abstract. The quasi-biennial oscillation (QBO) in tropical winds perturbs stratospheric ozone throughout much of the atmosphere via changes in transport of ozone and other trace gases and via temperature changes that alter chemical processes. Here we separate the temperature-driven changes using the Department of Energy’s Energy Exascale Earth System Model version 2 (E3SMv2) with linearized stratospheric ozone chemistry. E3SM produces a natural QBO cycle in winds, temperature, and ozone. Our analysis defines climatological QBO patterns of ozone for the period 1979–2020 using both nonlinear principal component analysis and monthly composites centered on QBO phase shift. As a climate model, E3SM cannot predict the timing of the phase shift, but it does match these climatological patterns. We develop an offline version of our stratospheric chemistry module to calculate the steady-state response of ozone to temperature and overhead ozone perturbations, assuming that other chemical families involved in ozone chemistry remain fixed. We find a clear demarcation: ozone perturbations in the upper stratosphere (above 20-hPa) are predicted by the steady-state response of the ozone column to the temperature changes; while those in the lower stratosphere show no temperature response and are presumably driven by circulation changes. These results are important for diagnosing model-model differences in the QBO-ozone responses for climate projections.

中文翻译：

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解开准两年期振荡对平流层臭氧的化学和运输影响


摘要。热带风中的准两年振荡（QBO）通过臭氧和其他微量气体传输的变化以及改变化学过程的温度变化扰乱了大部分大气中的平流层臭氧。在这里，我们使用能源部的能源百兆级地球系统模型版本 2 (E3SMv2) 和线性平流层臭氧化学来分离温度驱动的变化。 E3SM 产生风、温度和臭氧的自然 QBO 循环。我们的分析使用非线性主成分分析和以 QBO 相移为中心的月度合成数据，定义了 1979-2020 年期间臭氧的气候 QBO 模式。作为气候模型，E3​​SM 无法预测相移的时间，但它确实符合这些气候模式。我们开发了平流层化学模块的离线版本，以计算臭氧对温度和头顶臭氧扰动的稳态响应，假设参与臭氧化学的其他化学族保持固定。我们发现了一个明确的界限：平流层上层（20 hPa 以上）的臭氧扰动是通过臭氧柱对温度变化的稳态响应来预测的；而平流层低层的那些则没有表现出温度响应，并且可能是由环流变化驱动的。这些结果对于诊断气候预测 QBO 臭氧响应的模型间差异非常重要。