Retrieving tropospheric NO2 vertical column densities around the city of Beijing and estimating NOx emissions based on carMAX-DOAS measurements

doi:10.5194/acp-2020-316

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-316
	Retrieving tropospheric NO₂ vertical column densities around the city of Beijing and estimating NO_x emissions based on carMAX-DOAS measurements
	Xinghong Cheng, Jianzhong Ma, Junli Jin, Junrang Guo, Yuelin Liu, Jida Peng, Xiaodan Ma, Minglong Qian, Qiang Xia, and Peng Yan
	2020-06-22
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
英文摘要	We carried out 19 city-circle-around car MAX-DOAS experiments on the 6th Ring Road of Beijing in January, September, and October 2014. The tropospheric vertical column densities (VCDs) of NO₂ were retrieved from measured spectra by the Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) technique and used to estimate the emissions of NO_x (≡ NO + NO₂) from urban Beijing during the experimental periods. The offline LAPS-WRF-CMAQ model system was used to simulate the wind fields by assimilation of observational data and calculate the NO₂-to-NO_x concentration ratios, both of which are also needed for the estimation of NO_x emissions. The NOX emissions in urban Beijing for the different seasons derived from the car MAX-DOAS measurements in this study were compared to the multi-resolution emission inventory in China for 2012 (MEIC 2012). Our car MAX-DOAS measurement results showed higher NO₂ VCD in January than in the other two months and typically larger NO₂ VCD at the southern parts of the 6th Ring Road than at the northern parts. The wind field had obvious impacts on the spatial distribution of NO₂ VCD, with the mean NO₂ VCD along the 6th Ring Road typically being higher under the south wind than under the north wind. In addition to the seasonal difference, the journey-to-journey variations of estimated NO_x emissions rates (E_{NO_x}) were large even within the same month, mainly due to uncertainties in the calculations of wind speed, the ratio of NO₂ and NO_x concentration, and the decay rate of NO_x from the emission sources to the measured positions under different meteorological conditions. The ranges of E_{NO_x} during the heating and non-heating periods were 28.7 × 1025 to 60.0 × 1025 molecules s⁻¹ and 7.7 × 1025 to 24.8 × 1025 molecules s⁻¹, respectively. The average E_{NO_x} values in the heating and non-heating periods were 43.0 × 1025 molecules s⁻¹ and 13.9 × 1025 molecules s⁻¹, respectively. The uncertainty range of E_{NO_x} was 16.4–33.2 %. The monthly emission rates from MEIC 2012 are found to be lower than the estimated ENOX, particularly in January. Our results provide important information and datasets for the validation of satellite products and also show how car MAX-DOAS measurements can be used effectively for dynamic monitoring and updating of the NO_x emissions from megacities such as Beijing.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/278134
专题	地球科学
推荐引用方式 GB/T 7714	Xinghong Cheng, Jianzhong Ma, Junli Jin, Junrang Guo, Yuelin Liu, Jida Peng, Xiaodan Ma, Minglong Qian, Qiang Xia, and Peng Yan. Retrieving tropospheric NO₂ vertical column densities around the city of Beijing and estimating NO_x emissions based on carMAX-DOAS measurements[J]. Atmospheric Chemistry and Physics,2020.
APA	Xinghong Cheng, Jianzhong Ma, Junli Jin, Junrang Guo, Yuelin Liu, Jida Peng, Xiaodan Ma, Minglong Qian, Qiang Xia, and Peng Yan.(2020).Retrieving tropospheric NO₂ vertical column densities around the city of Beijing and estimating NO_x emissions based on carMAX-DOAS measurements.Atmospheric Chemistry and Physics.
MLA	Xinghong Cheng, Jianzhong Ma, Junli Jin, Junrang Guo, Yuelin Liu, Jida Peng, Xiaodan Ma, Minglong Qian, Qiang Xia, and Peng Yan."Retrieving tropospheric NO₂ vertical column densities around the city of Beijing and estimating NO_x emissions based on carMAX-DOAS measurements".Atmospheric Chemistry and Physics (2020).