Abstract Coastal regions are frequently subject to higher concentrations of ozone (O3) than areas farther inland due to thermally-direct recirculation (e.g., sea/bay breezes) of pollutants during summer months. Along with high O3 concentrations on polluted days, a bay breeze (in this case, the Chesapeake Bay breeze) causes low-level convergence over the land, which can lead to deep convection even on days without any large-scale convective forcing, altering both the local flow pattern and the concentrations and distributions of pollutants. Presented here is a bay breeze and thunderstorm climatology for Edgewood, MD, a coastal site along the Chesapeake Bay, from June, July, and August 2011–2016 between 11 and 19 EST (UTC-5). Using meteorological data from the Maryland Department of the Environment (MDE), bay breezes are identified by an automated detection algorithm, the Bay-breeze Identification Algorithm (BIA), customized for the complex coastline of river inlets within the Chesapeake Bay area. Additionally, thunderstorm vs. non-thunderstorm days are analyzed using gridded Earth Networks lightning data (ENTLN) within an influential radius of the site. The effects of bay breezes and deep convection on local O3 is quantified. The highest daily conditional mean O3 for all years was observed on bay breeze days, and the lowest on days with thunderstorms only (no bay breeze). Additionally, 39% of O3 exceedance days within the analysis time period were also bay breeze days. However, as ozone precursor emissions have fallen, the relationship between bay breezes and high O3 has diminished. While days with thunderstorms only (no bay breeze) were associated with the lowest daily mean O3, there were O3 events on some thunderstorm days, especially if there was also a bay breeze. Twenty-four percent of the total ozone exceedance days had a thunderstorm, demonstrating that thunderstorm days should not be assumed to be clean days, as boundary-layer venting and downdraft mixing depends on the thunderstorm duration and type (e.g., non-frontal/pop-up convection allowed slightly higher O3 concentrations than did frontal convection). These results illustrate the significant role that localized meteorological events that are difficult to predict play in modulating air pollution where many of the world's cities lie – near bodies of water.

中文翻译：

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2011-2016 年海湾微风和雷暴环流对切萨皮克湾沿线地点地表臭氧的影响

摘要 由于夏季月份污染物的热直接再循环（例如海风/海湾微风），沿海地区经常比更远的内陆地区遭受更高浓度的臭氧 (O3)。随着污染天 O3 浓度高，海湾微风（在这种情况下，切萨皮克湾微风）会导致陆地上空的低层辐合，即使在没有任何大规模对流强迫的日子里，这也会导致深层对流，改变两者当地的流动模式以及污染物的浓度和分布。这里展示的是 2011 年 6 月、7 月和 2016 年 8 月美国东部时间 11 日至 19 日（UTC-5）切萨皮克湾沿岸地区埃奇伍德的湾风和雷暴气候。使用马里兰州环境部 (MDE) 的气象数据，海湾微风通过自动检测算法进行识别，即海湾微风识别算法 (BIA)，该算法针对切萨皮克湾地区内河流入口的复杂海岸线进行了定制。此外，使用站点影响半径内的网格地球网络闪电数据 (ENTLN) 分析雷暴与非雷暴天数。对海湾微风和深层对流对局部 O3 的影响进行了量化。在有海湾微风的日子里观测到所有年份的最高日条件平均 O3，在只有雷暴的日子里（没有海湾微风）最低。此外，分析时间段内 39% 的 O3 超标天数也是海湾微风天数。然而，随着臭氧前体排放量的下降，海湾微风和高 O3 之间的关系已经减弱。虽然只有雷暴的日子（没有海湾微风）与最低的日平均 O3 相关联，但在某些雷暴日会发生 O3 事件，尤其是在有海湾微风的情况下。总臭氧超标天数的 24% 有雷暴，这表明不应假定雷暴天是干净的天，因为边界层通风和下沉气流的混合取决于雷暴持续时间和类型（例如，非锋面/流行性向上对流允许的 O3 浓度略高于正面对流）。这些结果说明了难以预测的局部气象事件在调节世界上许多城市靠近水体的空气污染方面发挥的重要作用。特别是如果还有海湾微风。总臭氧超标天数的 24% 有雷暴，这表明不应假定雷暴天是干净的天，因为边界层通风和下沉气流的混合取决于雷暴持续时间和类型（例如，非锋面/流行性向上对流允许的 O3 浓度略高于正面对流）。这些结果说明了难以预测的局部气象事件在调节世界上许多城市靠近水体的空气污染方面发挥的重要作用。特别是如果还有海湾微风。总臭氧超标天数的 24% 有雷暴，这表明不应假定雷暴天是干净的天，因为边界层通风和下沉气流的混合取决于雷暴持续时间和类型（例如，非锋面/流行性向上对流允许的 O3 浓度略高于正面对流）。这些结果说明了难以预测的局部气象事件在调节世界上许多城市靠近水体的空气污染方面发挥的重要作用。因为边界层通风和下沉气流的混合取决于雷暴持续时间和类型（例如，非锋面/弹出对流允许的 O3 浓度略高于锋面对流）。这些结果说明了难以预测的局部气象事件在调节世界上许多城市靠近水体的空气污染方面发挥的重要作用。因为边界层通风和下沉气流的混合取决于雷暴持续时间和类型（例如，非锋面/弹出对流允许的 O3 浓度略高于锋面对流）。这些结果说明了难以预测的局部气象事件在调节世界上许多城市靠近水体的空气污染方面发挥的重要作用。