Investigations of temporal and spatial distribution of precursors SO2 and NO2 vertical columns in the North China Plain using mobile DOAS
Investigations of temporal and spatial distribution of precursors SO2 and NO2 vertical columns in the North China Plain using mobile DOAS
复制标题
利用移动DOAS研究华北平原前体SO2和NO2垂直柱的时空分布
DOI：
10.5194/acp-18-1535-2018
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发表时间：
2018-02-02
影响因子：
6.3
通讯作者：
Liu, Wenqing
中科院分区：
文献类型：
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作者：
Wu, Fengcheng;Xie, Pinhua;Liu, Wenqing
最近，中国城市遭受了严重的雾霾空气污染事件，特别是在北中国平原。为了更好地了解各种污染源对空气质量的影响，有必要调查污染物、排放和污染物传输的时空分布。本文报道了2013年夏季(6月11日至7月7日)NCP中SO2和NO2前驱体垂直柱的移动差分吸收光谱(MODAS)观测。研究了不同风场条件下该地区SO2和NO2垂直柱密度(VCD)的时空分布特征。结果表明，北太平洋南部输送对北京空气质量影响较大，确定了石家庄-保定-北京一带的输送路径，特别是SO2的输送路径。此外，石家庄-保定-北京沿线SO2的主要贡献者是高架源，而德州-沧州-天津-北京沿线的SO2主要是低面源，这是通过实测期的现场观测和移动DOAS观测的相关性分析得出的。此外，对济南市附近热点地区的讨论表明，污染气团的平均观测宽度为11.83公里，与空气质量扩散相关的平均宽度为17.23公里，根据几何估计，距离排放源约60公里。最后，臭氧监测仪(OMI)与移动DOAS观测之间存在合理的一致性，NO2 VCDs的相关系数(R-2)为0.65。这两个数据集也具有相似的空间模式。拟合斜率0.55明显小于1，反映了局地污染源的污染情况，需要通过改进反演算法或提高卫星分辨率来提高OMI观测对近地表排放源的灵敏度。
Recently, Chinese cities have suffered severe events of haze air pollution, particularly in the North China Plain (NCP). Investigating the temporal and spatial distribution of pollutants, emissions, and pollution transport is necessary to better understand the effect of various sources on air quality. We report on mobile differential optical absorption spectroscopy (mobile DOAS) observations of precursors SO2 and NO2 vertical columns in the NCP in the summer of 2013 (from 11 June to 7 July) in this study. The different temporal and spatial distributions of SO2 and NO2 vertical column density (VCD) over this area are characterized under various wind fields. The results show that transport from the southern NCP strongly affects air quality in Beijing, and the transport route, particularly SO2 transport on the route of Shijiazhuang-Baoding-Beijing, is identified. In addition, the major contributors to SO2 along the route of Shijiazhuang-Baoding- Beijing are elevated sources compared to low area sources for the route of Dezhou-Cangzhou-Tianjin-Beijing; this is found using the interrelated analysis between in situ and mobile DOAS observations during the measurement periods. Furthermore, the discussions on hot spots near the city of JiNan show that average observed width of polluted air mass is 11.83 and 17.23 km associated with air mass diffusion, which is approximately 60 km away from emission sources based on geometrical estimation. Finally, a reasonable agreement exists between the Ozone Monitoring Instrument (OMI) and mobile DOAS observations, with a correlation coefficient (R-2) of 0.65 for NO2 VCDs. Both datasets also have a similar spatial pattern. The fitted slope of 0.55 is significantly less than unity, which can reflect the contamination of local sources, and OMI observations are needed to improve the sensitivities to the near-surface emission sources through improvements of the retrieval algorithm or the resolution of satellites.