Spectroscopy and Spectral Analysis, Volume. 43, Issue 6, 1725(2023)

Spectral Inversion and Variation Characteristics of Tropospheric NO2 Column Density in Lhasa, Tibet

PU Gui-juan1, CHENG Si-yang2, LI Song-kui3, LV Jin-guang4, CHEN Hua5, and MA Jian-zhong2
Author Affiliations
  • 1[in Chinese]
  • 2[in Chinese]
  • 3[in Chinese]
  • 4[in Chinese]
  • 5[in Chinese]
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    The observation of solar scattering spectra was performed at Lhasa by Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS), which was used to retrieve the tropospheric vertical column densities (VCDtrop) of nitrogen dioxide (NO2) in order to investigate the variation characteristics of NO2 during the celebration period of the 70th anniversary of the peaceful liberation of Tibet. During the observation period (9 August 2021 to 31 August 2021), the averaged NO2 VCDtrop in the daytime was 4.46×1015 molec·cm-2, significantly higher than that on the celebration day of the 70th anniversary of the peaceful liberation of Tibet (2.85×1015 molec·cm-2). In addition, the daily averages of NO2 VCDtrop presented a good correlation with the results measured by the online surface observation, with a correlation coefficient of 0.58. During the observation experiment, the prevailing wind direction in Lhasa was westerly, and the east-west direction was the transport path of atmospheric NO2, which was consistent with the river valley topography of Lhasa city. The average diurnal variation of the hourly means of NO2 VCDtrop showed a “U” pattern, with higher values appearing in the morning and evening, and lower values occurring around 16:00. However, on the celebration day of the 70th anniversary of the peaceful liberation of Tibet, the diurnal variation of NO2 VCDtrop not only presented the peak values in the morning and evening but also at noon, which probably was related to the removal of road control measures after the activity and the emission of support vehicle. In conclusion, this study confirmed the good applicability of ground-based MAX-DOAS remote sensing in the typical city of Lhasa over the Tibetan Plateau. Meanwhile, it was also found that the level and variation of NO2 VCDtrop in Lhasa were mainly affected by urban traffic emissions. The atmospheric NO2 concentration in Lhasa was lower on the celebration day of the 70th anniversary of the peaceful liberation of Tibet.

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    PU Gui-juan, CHENG Si-yang, LI Song-kui, LV Jin-guang, CHEN Hua, MA Jian-zhong. Spectral Inversion and Variation Characteristics of Tropospheric NO2 Column Density in Lhasa, Tibet[J]. Spectroscopy and Spectral Analysis, 2023, 43(6): 1725

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    Paper Information

    Received: Mar. 21, 2022

    Accepted: --

    Published Online: Jan. 8, 2024

    The Author Email:

    DOI:10.3964/j.issn.1000-0593(2023)06-1725-06

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