Laser & Optoelectronics Progress, Volume. 59, Issue 19, 1901002(2022)
Stageful Characteristics of Aerosol Spectral Distribution and Optical Properties During a Dust Episode in Shouxian
Observation data of aerosol vertical distribution, particle number concentration, mass concentration, scattering characteristics, and visibility were captured using three-wavelength polarization lidar and online aerosol-monitoring instruments during a dust episode at Shouxian National Climate Observatory from January 14 to 16, 2021. These data, combined with the conventional surface meteorological observation data, were then used for analyzing the stageful evolution characteristics of aerosol microphysics, optical properties, and vertical distribution during the dust episode. The results show that the peak value of the total number concentration of aerosol particles in the transit of dust is 5431 cm-3, the mass fraction peak value of PM10 is 447.2 μg/m3, and the mass fraction ratio between PM2.5 and PM10 is 0.43±0.10. Furthermore, the aerosol spectrum distribution in the dust, haze, and clear-sky stages could be expressed as the superposition of two fine-grained modes and one coarse-grained mode. The number concentration of aerosol particles in the dust stage is significantly higher than that in the haze and clear-sky stages, and the geometric average radius of particles in the two fine-grained modes is basically the same. In the coarse-grained mode, the geometric average radius of particles in the dust stage is 2.24 μm, which is significantly higher than 1.74 μm in the clear-sky stage and 1.79 μm in the haze stage. The average value of the total scattering coefficient in the dust stage is greater than those in the haze and clear-sky stages. In the dust stage, the backscattering ratio of the aerosol particles is found to be smaller, indicating that the air is dominated by larger dust particles. The vertical distribution trend of the aerosol-extinction coefficient at three wavelengths is found to be basically the same, and the extinction coefficient in the dust stage is greater than those in the haze and clear-sky stages. The height of the aerosol layer in the dust stage extends to 3 km near the ground, the depolarization ratio is basically greater than 0.1, and the Angstr?m index is in the range 0.1?0.4.
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Debao Dong, Guangyuan Zhang, Dachun Lu, Yue He. Stageful Characteristics of Aerosol Spectral Distribution and Optical Properties During a Dust Episode in Shouxian[J]. Laser & Optoelectronics Progress, 2022, 59(19): 1901002
Category: Atmospheric Optics and Oceanic Optics
Received: May. 9, 2022
Accepted: Jun. 22, 2022
Published Online: Sep. 6, 2022
The Author Email: Dong Debao (ddbao@mail.ustc.edu.cn)