Optical and microphysical properties of natural mineral dust and anthropogenic soil dust near dust source regions over northwestern China

Abstract

Abstract. Mineral dust aerosols (MDs) not only influence the climate by scattering and absorbing solar radiation but also modify cloud properties and change the ecosystem. From 3 April to 16 May 2014, a ground-based mobile laboratory was deployed to measure the optical and microphysical properties of MDs near dust source regions in Wuwei, Zhangye, and Dunhuang (in chronological order) along the Hexi Corridor over northwestern China. Throughout this dust campaign, the hourly averaged (±standard deviation) aerosol scattering coefficients (σ sp , 550 nm) of the particulates with aerodynamic diameters less than 2.5 µm (PM 2.5 ) at these three sites were sequentially 101.5 ± 36.8, 182.2 ± 433.1, and 54.0 ± 32.0 Mm −1 . Correspondingly, the absorption coefficients (σ ap , 637 nm) were 9.7 ± 6.1, 6.0 ± 4.6, and 2.3 ± 0.9 Mm −1 ; single-scattering albedos (ω, 637 nm) were 0.902 ± 0.025, 0.931 ± 0.037, and 0.949 ± 0.020; and scattering Ångström exponents (Å sp , 450-700 nm) of PM 2.5 were 1.28 ± 0.27, 0.77 ± 0.51, and 0.52 ± 0.31. During a severe dust storm in Zhangye (i.e., from 23 to 25 April), the highest values of σ 2.5 sp (∼ 5074 Mm −1 ), backscattering coefficient (σ 2.5 bsp , ∼ 522 Mm −1 ), and ω 637 (∼ 0.993) and the lowest values of backscattering fraction (b 2.5 , ∼ 0.101) at 550 nm and Å 2.5 sp (∼ −0.046) at 450-700 nm, with peak values of aerosol number size distribution (appearing at the particle diameter range of 1-3 µm), exhibited that the atmospheric aerosols were dominated by coarse-mode dust aerosols. It is hypothesized that the relatively higher values of mass scattering efficiency during floating dust episodes in Wuwei and Zhangye are attributed to the anthropogenic soil dust produced by agricultural cultivations.

Satellite‐Observed Impacts of Wildfires on Regional Atmosphere Composition and the Shortwave Radiative Forcing: A Multiple Case Study

“…The source of atmospheric aerosol is complicated. For example, in the studying area in Northeastern China, the AOD can be significantly affected by mineral dust from the upstream Gobi and Taklimakan desert (Li et al, ; Wang, Liu, et al, ; Wang, Wen, et al, ), and in that case, AOD has no correlations with trace gases. Therefore, the good correlation shown in Figure indicated that those pollutants were mainly emitted from the fire and transported downwind.…”

Characterization of atmospheric bioaerosols along the transport pathway of Asian dust during the Dust-Bioaerosol 2016 Campaign

“…In Japan, the concentrations of bacterial cells and the structure of airborne bacterial communities in the near-surface air and the free troposphere are affected by Asian dust events (Maki et al, 2014(Maki et al, , 2015. Similarly, the yellow sandstorms that originate in Asian deserts have been reported to affect the ambient air quality of Taiwan by increasing the levels of fungal spores (Ho et al, 2005;Wu et al, 2004). Results from South Korea also show that Asian dust impacts both airborne fungal concentrations and fungal communities (Jeon et al, 2011(Jeon et al, , 2013Yeo and Kim, 2002).…”

The reviewed supplement with tracking changes

“…In Japan, the concentrations of bacterial cells and the structure of airborne bacterial communities in the near-surface air and the free troposphere are affected by Asian dust events . Similarly, the yellow sandstorms that originate in Asian deserts have been reported to affect the ambient air quality of Taiwan by increasing the levels of fungal spores (Ho et al, 2005;Wu et al, 2004). Results from South Korea also show that Asian dust impacts both airborne fungal concentrations and fungal communities (Jeon et al, 2011(Jeon et al, , 2013Yeo and Kim, 2002).…”