Abstract Ozone is one of remaining air quality issues in Japan. Effective strategies are required to reduce ozone at the ground level. Regional chemical transport models are useful in investigating relationships between precursor emissions and ambient concentrations of secondary pollutants including ozone. Model performance on ozone concentrations over urban areas in Japan were thoroughly evaluated in model inter-comparisons conducted in Japan's study for reference air quality modeling (J-STREAM). Specifically, 33 models with different configurations including the Community Multiscale Air Quality Modeling System (CMAQ), the Comprehensive Air Quality Model with Extensions (CAMx), and the Weather Research and Forecasting (WRF) model coupled with Chemistry (WRF-Chem) participated. They realized inter-comparisons with an unprecedented number of different model configurations. All the participating models overestimated ozone concentrations by 22 ± 4.6 ppb over urban areas in Japan during the summer. Spatial and temporal variations in model performance suggest the influence of background ozone concentrations. Based on differences in the participating model configurations, halogen chemistry and deposition, dry deposition velocity, precursor emissions in other countries, and vertical transport were identified as the key factors influencing simulated background ozone concentrations. Specific sensitivity analyses were conducted to evaluate the effects of the key influencing factors. Halogen chemistry and deposition implemented in recent versions of CMAQ caused more than 10 ppb reduction of simulated ozone over the ocean surrounding Japan, while the original dry deposition schemes used in CAMx and WRF-Chem, without any effect of halogen, can also cause larger dry deposition. Horizontal and downward transport of ozone kept in a residual layer over the continent can spread the effect of precursor emissions in other countries to downwind regions, including Japan. Differences in vertical transport can alter the spatial extent of their effects. It is essential to improve the influence of the aforementioned key factors to realize better model performance on ozone concentrations over urban areas, not only in Japan, but all over the world.

中文翻译：

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通过模型比对确定影响日本城市地区地面臭氧模型性能的关键因素

摘要 臭氧是日本遗留的空气质量问题之一。需要有效的战略来减少地面臭氧。区域化学传输模型可用于研究前体排放与二次污染物（包括臭氧）的环境浓度之间的关系。在日本参考空气质量建模研究 (J-STREAM) 中进行的模型相互比较中，对日本城市地区臭氧浓度的模型性能进行了彻底评估。具体而言，包括社区多尺度空气质量建模系统（CMAQ）、带扩展的综合空气质量模型（CAMx）、天气研究与预测（WRF）与化学结合的模型（WRF-Chem）等33个不同配置的模型参与。他们实现了与空前数量的不同模型配置的相互比较。所有参与模型都将夏季日本城市地区的臭氧浓度高估了 22 ± 4.6 ppb。模型性能的时空变化表明背景臭氧浓度的影响。根据参与模型配置的差异，卤素化学和沉积、干沉积速度、其他国家的前体排放和垂直传输被确定为影响模拟背景臭氧浓度的关键因素。进行了特定的敏感性分析，以评估关键影响因素的影响。最新版本的 CMAQ 中实施的卤素化学和沉积导致日本周围海洋上模拟的臭氧减少 10 ppb 以上，而 CAMx 和 WRF-Chem 中使用的原始干沉积方案，没有卤素的任何影响，也可能导致更大的干沉积沉积。保持在大陆上空残留层中的臭氧的水平和向下传输可以将其他国家的前体排放的影响传播到包括日本在内的顺风地区。垂直运输的差异可以改变其影响的空间范围。必须改善上述关键因素的影响，以实现更好的模型对城市地区臭氧浓度的影响，不仅在日本，而且在全世界。没有卤素的任何影响，也会造成较大的干沉积。保持在大陆上空残留层中的臭氧的水平和向下传输可以将其他国家的前体排放的影响传播到包括日本在内的顺风地区。垂直运输的差异可以改变其影响的空间范围。必须改善上述关键因素的影响，以实现更好的模型对城市地区臭氧浓度的影响，不仅在日本，而且在全世界。没有卤素的任何影响，也会造成较大的干沉积。保持在大陆上空残留层中的臭氧的水平和向下传输可以将其他国家的前体排放的影响传播到包括日本在内的顺风地区。垂直运输的差异可以改变其影响的空间范围。必须改善上述关键因素的影响，以实现更好的模型对城市地区臭氧浓度的影响，不仅在日本，而且在全世界。