A closure study of aerosol optical properties as a function of RH using a κ-AMS-BC-Mie model in Beijing, China

2019 ◽  
Vol 197 ◽  
pp. 1-13 ◽  
Author(s):  
Jianan Zou ◽  
Shuanghong Yang ◽  
Bo Hu ◽  
Zirui Liu ◽  
Wenkang Gao ◽  
...  
2017 ◽  
Vol 166 ◽  
pp. 340-350 ◽  
Author(s):  
Xingna Yu ◽  
Rui Lü ◽  
Chao Liu ◽  
Liang Yuan ◽  
Yixing Shao ◽  
...  

2017 ◽  
Vol 1 (2) ◽  
pp. 78-92 ◽  
Author(s):  
Jie Yu ◽  
Huizheng Che ◽  
Quanliang Chen ◽  
Hongbin Chen ◽  
Philippe Goloub ◽  
...  

2022 ◽  
Vol 22 (1) ◽  
pp. 561-575
Author(s):  
Jiaxing Sun ◽  
Zhe Wang ◽  
Wei Zhou ◽  
Conghui Xie ◽  
Cheng Wu ◽  
...  

Abstract. Atmospheric aerosols play an important role in the radiation balance of the earth–atmosphere system. However, our knowledge of the long-term changes in equivalent black carbon (eBC) and aerosol optical properties in China is very limited. Here we analyze the 9-year measurements of eBC and aerosol optical properties from 2012 to 2020 in Beijing, China. Our results showed large reductions in eBC by 71 % from 6.25 ± 5.73 µg m−3 in 2012 to 1.80 ± 1.54 µg m−3 in 2020 and 47 % decreases in the light extinction coefficient (bext, λ = 630 nm) of fine particles due to the Clean Air Action Plan that was implemented in 2013. The seasonal and diurnal variations of eBC illustrated the most significant reductions in the fall and at nighttime, respectively. ΔeBC / ΔCO also showed an annual decrease from ∼ 7 to 4 ng m−3 ppbv−1 and presented strong seasonal variations with high values in spring and fall, indicating that primary emissions in Beijing have changed significantly. As a response to the Clean Air Action Plan, single-scattering albedo (SSA) showed a considerable increase from 0.79 ± 0.11 to 0.88 ± 0.06, and mass extinction efficiency (MEE) increased from 3.2 to 3.8 m2 g−1. These results highlight the increasing importance of scattering aerosols in radiative forcing and a future challenge in visibility improvement due to enhanced MEE. Brown carbon (BrC) showed similar changes and seasonal variations to eBC during 2018–2020. However, we found a large increase of secondary BrC in the total BrC in most seasons, particularly in summer with the contribution up to 50 %, demonstrating an enhanced role of secondary formation in BrC in recent years. The long-term changes in eBC and BrC have also affected the radiative forcing effect. The direct radiative forcing (ΔFR) of BC decreased by 67 % from +3.36 W m−2 in 2012 to +1.09 W m−2 in 2020, and that of BrC decreased from +0.30 to +0.17 W m−2 during 2018–2020. Such changes might have important implications for affecting aerosol–boundary layer interactions and the improvement of future air quality.


2008 ◽  
Vol 8 (12) ◽  
pp. 3199-3214 ◽  
Author(s):  
H. Che ◽  
G. Shi ◽  
A. Uchiyama ◽  
A. Yamazaki ◽  
H. Chen ◽  
...  

Abstract. This study compares the aerosol optical and physical properties simultaneously measured by a SKYNET PREDE skyradiometer and AERONET/PHOTONS CIMEL sunphotometer at a location in Beijing, China. Aerosol optical properties (AOP) including the Aerosol Optical Depth (AOD), Angstrom exponent (α), volume size distribution, single scattering albedo (ω) and the complex refractive index were compared. The difference between the two types of instruments was less than 1.3% for the AOD and less than 4% for the single scattering albedo below the wavelength of 670 nm. There is a difference between the volume size distribution patterns derived from two instruments, which is probably due to difference of measurement protocols and inversion algorithms for the respective instruments. AOP under three distinct weather conditions (background, haze, and dust days) over Beijing were compared by using the retrieved skyradiometer and sunphotometer data combined with MODIS satellite results, pyranometer measurements, PM10 measurements, and backtrajectory analysis. The results show that the significant difference of AOP under background, haze, and dust days over Beijing is probably due to different aerosol components under distinct weather conditions.


2014 ◽  
Vol 92A (0) ◽  
pp. 17-31 ◽  
Author(s):  
Huizheng CHE ◽  
Guangyu SHI ◽  
Hujia ZHAO ◽  
Teruyuki NAKAJIMA ◽  
Pradeep KHATRI ◽  
...  

2021 ◽  
Author(s):  
Jiaxing Sun ◽  
Zhe Wang ◽  
Wei Zhou ◽  
Conghui Xie ◽  
Cheng Wu ◽  
...  

Abstract. Atmospheric aerosols play an important role in radiation balance of the earth-atmosphere system. However, our knowledge of the long-term changes in black carbon (BC) and aerosol optical properties in China are very limited. Here we analyze the nine-year measurements of BC and aerosol optical properties from 2012 to 2020 in Beijing, China. Our results showed large reductions in eBC by 67 % from 5.54 ± 5.25 µg m−3 in 2012 to 1.80 ± 1.54 µg m−3 in 2020, and 47 % decreases in light extinction coefficient (bext, λ = 630 nm) of fine particles due to clean air action plan since 2013. The seasonal and diurnal variations of eBC illustrated the most significant reductions in the fall and night time, respectively. ΔeBC/ΔCO also showed an annual decrease from ~6 to 4 ng m−3 ppbv−1 and presented strong seasonal variations with high values in spring and fall, indicating that primary emissions in Beijing have changed significantly. As a response to clean air action, single scattering albedo (SSA) showed a considerable increase from 0.79 ± 0.11 to 0.88 ± 0.06, and mass extinction efficiency (MEE) increased from 3.2 to 3.8 m2 g−1. These results highlight an increasing importance of scattering aerosols in radiative forcing, and a future challenge in visibility improvement due to enhanced MEE. Brown carbon (BrC) showed similar changes and seasonal variations to eBC during 2018–2020. However, we found a large increase of secondary BrC in the total BrC in most seasons, particularly in summer with the contribution up to 50 %, demonstrating an enhanced role of secondary formation in BrC in recent years. The long-term changes in eBC and BrC have also affected the radiative forcing effect. The direct radiative forcing (ΔFR) of BC decreased by 64 % from +3.00 W m−2 in 2012 to +1.09 W m−2 in 2020, and that of BrC decreased from +0.30 to +0.17 W m−2 during 2018–2020. Such changes might have important implications in affecting aerosol and boundary-layer interactions and the future air quality improvement.


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