Abstract Surface observations collected over the period 1980–2010 at three Continuous Ambient Monitoring Stations located in Houston, Texas were leveraged to create a long-term composite dataset of tropospheric ozone measurements. This dataset was used to evaluate large-scale influences and their relationship to exceedances of the 70 ppbv National Ambient Air Quality Standard for ozone. A linear regression fit to monthly mean daily peak 8-h concentrations for each month revealed a decreasing trend for the duration of the study period. After removal of this temporal trend, 8-h peak values averaged for each month featured peaks in springtime and late-summer with relative minima in mid-summer and winter. Stratification of the database by El Nino-Southern Oscillation phase using the Oceanic Nino Index revealed a statistically significant (α = 0.05) dependence of peak 8-h concentration on ENSO phase, with an enhancement of 5.8, 4.8, and 7.0 for March, April, and June during warm phase years, while cool phase years had statistically significant enhancements of 5.0, 4.0, and 3.6 ppbv in February, October, and December relative to neutral conditions. Importantly, relative to neutral conditions, “El Nino years” produce 26% more exceedences while “La Nina years” produce 23% fewer. The earlier onset of ozone seasons both in spring and late summer during El Nino years leads to more exposure to direct sunlight and more seasonal photochemical production, while the delayed late summer season during La Nina years leads to decreased sunlight and suppressed seasonal photochemical production relative to neutral years. Evaluation of the number of exceedances per month for each ENSO regime also suggests high tropospheric ozone concentrations in the fall and spring, with 4.4 and 6.8 exceedances per month in June and September, respectively for the warm phase. During cool phase conditions, Houston averaged 5.0 exceedances per month in September. Exceedances for neutral conditions ranged from zero exceedances in December to 2.2 exceedances in May and 5.0 in September. Analysis of exceedance data and mean values in light of parameters of the underlying distribution of daily peak 8-h data suggests that ENSO may influence the shape of those distributions, influencing both background ozone concentrations and the number of exceedances. Fast Fourier analysis indicated a common spectral signature for the ENSO and ozone spectra. This finding has implications for air quality mitigation strategies employed during warm phase and cool phase years.

中文翻译：

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厄尔尼诺-南方涛动对休斯顿 30 年对流层臭氧浓度影响的评估

摘要 1980 年至 2010 年期间在位于德克萨斯州休斯顿的三个连续环境监测站收集的地表观测资料被用来创建对流层臭氧测量的长期复合数据集。该数据集用于评估大规模影响及其与超过 70 ppbv 国家环境空气质量标准臭氧的关系。对每月平均每日峰值 8 小时浓度的线性回归拟合显示研究期间的持续时间呈下降趋势。去除这种时间趋势后，每个月的平均 8 小时峰值在春季和夏末出现峰值，而在仲夏和冬季相对最小值。使用海洋尼诺指数通过厄尔尼诺 - 南方涛动阶段对数据库进行分层显示具有统计显着性（α = 0。05) 8 小时峰值浓度对 ENSO 阶段的依赖性，在暖相年份的 3 月、4 月和 6 月分别增加了 5.8、4.8 和 7.0，而在凉爽相年的统计上增加了 5.0、4.0 和 3.6相对于中性条件，2 月、10 月和 12 月的 ppbv。重要的是，相对于中性条件，“厄尔尼诺年”产生的超标量增加了 26%，而“拉尼娜年”产生的排放量减少了 23%。厄尔尼诺年春季和夏末臭氧季节的提前开始导致更多的阳光直射和更多的季节性光化学生产，而拉尼娜年的夏末季节延迟导致阳光减少并抑制季节性光化学生产。中性年。对每个 ENSO 制度每月超标次数的评估还表明，秋季和春季对流层臭氧浓度较高，6 月和 9 月的暖期分别为每月 4.4 和 6.8 次超标。在凉爽的阶段条件下，休斯顿 9 月平均每月超过 5.0 次。中性条件的超标范围从 12 月的零超标到 5 月的 2.2 超标和 9 月的 5.0 超标。根据每日峰值 8 小时数据的基本分布参数对超标数据和平均值进行分析表明，ENSO 可能会影响这些分布的形状，从而影响背景臭氧浓度和超标次数。快速傅立叶分析表明 ENSO 和臭氧光谱具有共同的光谱特征。