Tropospheric NO2 column densities deduced from zenith-sky DOAS measurements in Shanghai, China, and their application to satellite validation
Tropospheric NO2 column densities deduced from zenith-sky DOAS measurements in Shanghai, China, and their application to satellite validation
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DOI：
10.5194/acp-9-3641-2009
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发表时间：
2009-01-01
影响因子：
6.3
通讯作者：
Wagner, T.
中科院分区：
文献类型：
--
作者：
Chen, D.;Zhou, B.;Wagner, T.
自2006年12月以来，在中国上海（北纬31.3度，东经121.5度）利用差分光学吸收光谱（DOAS）技术进行了天顶-天空散射太阳光观测。在这个被污染的城市地点，测量结果提供了白天的二氧化氮总柱数。本文提出了一种利用这些观测数据提取对流层NO2垂直柱密度（VCDs）时间序列的新方法。导出的对流层NO2 vcd是估算排放和验证卫星观测的重要量。我们的方法利用了对相对NO2高度剖面和平流层NO2 vcd的日变化的假设。误差的主要来源是平流层斜柱密度（SCDs）估算和对流层NO2气团因子（AMF）测定的不确定性。对于像上海这样的污染场地，我们的方法的精度保守估计为
Zenith-sky scattered sunlight observations using differential optical absorption spectroscopy (DOAS) technique were carried out in Shanghai, China (31.3 degrees N, 121.5 degrees E) since December 2006. At this polluted urban site, the measurements provided NO2 total columns in the daytime. Here, we present a new method to extract time series of tropospheric vertical column densities (VCDs) of NO2 from these observations. The derived tropospheric NO2 VCDs are important quantities for the estimation of emissions and for the validation of satellite observations. Our method makes use of assumptions on the relative NO2 height profiles and the diurnal variation of stratospheric NO2 VCDs. The main error sources arise from the uncertainties in the estimated stratospheric slant column densities (SCDs) and the determination of tropospheric NO2 air mass factor (AMF). For a polluted site like Shanghai, the accuracy of our method is conservatively estimated to be