Spectral Inversion and Characteristics of NO2 Column Density at Shangdianzi Regional Atmospheric Background Station
CHENG Si-yang1, MA Jian-zhong1*, ZHOU Huai-gang2, JIN Jun-li3, LIU Yan4, DONG Fan2, ZHOU Li-yan2, YAN Peng1, 3
1. State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of China Meteorological Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China
2. Shangdianzi Regional Air Background Station, Beijing Meteorological Bureau, Beijing 101507, China
3. China Meteorological Administration Meteorological Observation Center, Beijing 100081, China
4. College of Geographic Science and Tourism，Xinjiang Normal University，Urumqi 830054，China
Abstract：In order to explore the variation characteristics of significant air pollutant NO2 in the Beijing-Tianjin-Hebei background region, the Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) was used to record solar scattering spectra at Shangdianzi regional atmospheric background station and retrieve the NO2 column densities. Quantitative spectral analysis was carried out in the characteristic wavelength of NO2 405～430 nm. The NO2 tropospheric vertical column densities (VCDtrop) from July 2009 to September 2009 were calculated through geometric approximation. The mean and maximum value of NO2 VCDtrop were 5.43×1015 and 7.15×1016 molec·cm-2 during the observation period, respectively. The daily NO2 VCDtrop was lower, but there was an upward trend as a whole. The variation of NO2 VCDtrop was closely related to wind speed and direction: NO2 VCDtrop concentration was lower when southwesterly wind was weaker, and the northeasterly wind was conducive to the NO2 diffusion. Generally, diurnal variations of NO2 VCDtrop showed the characteristics of being low at noon and high in the morning and evening, and the evening peak was slightly higher than the morning one. The level and diurnal range of NO2 VCDtrop at Shangdianzi station were significantly smaller than the results in the Beijing city over the same period. These variation characteristics were consistent with the ones at the mild pollution stations of Xianghe and Gucheng in Hebei. In a word, reginal background atmospheric NO2 VCDtrop can be effectively monitored by MAX-DOAS, although the characteristics were related to complex factors such as industrial and traffic emission, photochemical reaction and atmospheric transport. More data are necessary for further study.
Key words：MAX-DOAS; NO2; Column density; Regional atmospheric background station
