Total-column nitrogen dioxide (NO2) data collected by a ground-based sun-tracking spectrometer system (Pandora) and an photolytic-converter-based in-situ instrument collocated at NASA’s Langley Research Center in Hampton, Virginia were analyzed to study the relationship between total-column and surface NO2 measurements. The measurements span more than a year and cover all seasons. Surface mixing ratios are estimated via application of a planetary boundary-layer (PBL) height correction factor. This PBL correction factor effectively corrects for boundary-layer variability throughout the day, and accounts for up to ≈75 % of the variability between the NO2 data sets. Previous studies have made monthly and seasonal comparisons of column/surface data, which has shown generally good agreement over these long average times. In the current analysis comparisons of column densities averaged over 90 s and 1 h are made. Applicability of this technique to sulfur dioxide (SO2) is briefly explored. The SO2 correlation is improved by excluding conditions where surface levels are considered background. The analysis is extended to data from the July 2011 DISCOVER-AQ mission over the greater Baltimore, MD area to examine the method’s performance in more-polluted urban conditions where NO2 concentrations are typically much higher.

中文翻译：

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从快速响应总柱观测和对地球静止任务的潜在应用估计地表 NO2 和 SO2 混合比

分析由位于弗吉尼亚州汉普顿的 NASA 兰利研究中心的地面太阳跟踪光谱仪系统 (Pandora) 和基于光解转换器的原位仪器收集的总柱二氧化氮 (NO2) 数据，以研究这种关系在总柱和表面 NO2 测量之间。测量跨越一年多，涵盖所有季节。表面混合比是通过应用行星边界层 (PBL) 高度校正因子来估计的。该 PBL 校正因子有效地校正了全天的边界层变化，并解释了 NO2 数据集之间高达 ≈75% 的变化。以前的研究已经对柱/表面数据进行了月度和季节比较，在这些长的平均时间内显示出普遍良好的一致性。在当前的分析中，对 90 秒和 1 小时内的平均柱密度进行了比较。简要探讨了该技术对二氧化硫 (SO2) 的适用性。通过排除表面水平被视为背景的条件，SO2 相关性得到改善。该分析扩展到 2011 年 7 月 DISCOVER-AQ 任务在马里兰州巴尔的摩地区的数据，以检查该方法在二氧化氮浓度通常更高的污染更严重的城市条件下的性能。