Monthly and seasonal variations of aerosol optical properties and direct radiative forcing over Zanjan, Iran

2017 ◽  
Vol 164 ◽  
pp. 268-275 ◽  
Author(s):  
Maryam Gharibzadeh ◽  
Khan Alam ◽  
Yousefali Abedini ◽  
Abbasali Aliakbari Bidokhti ◽  
Amir Masoumi
Keyword(s):  
Optical Properties ◽  
Seasonal Variations ◽  
Radiative Forcing ◽  
Aerosol Optical Properties ◽  
Direct Radiative Forcing

scholarly journals One year measurements of aerosol optical properties over an urban coastal site: Effect on local direct radiative forcing

2008 ◽  
Vol 90 (2-4) ◽  
pp. 195-202 ◽  
Author(s):  
Auromeet Saha ◽  
Marc Mallet ◽  
Jean Claude Roger ◽  
Philippe Dubuisson ◽  
Jacques Piazzola ◽  
...  
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Site Effect ◽  
Aerosol Optical Properties ◽  
Coastal Site ◽  
Direct Radiative Forcing ◽  
One Year

scholarly journals Measurement report: Long-term changes in black carbon and aerosol optical properties from 2012 to 2020 in Beijing, China

2022 ◽  
Vol 22 (1) ◽  
pp. 561-575
Author(s):  
Jiaxing Sun ◽  
Zhe Wang ◽  
Wei Zhou ◽  
Conghui Xie ◽  
Cheng Wu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Black Carbon ◽  
Seasonal Variations ◽  
Radiative Forcing ◽  
Action Plan ◽  
Aerosol Optical Properties ◽  
Long Term Changes ◽  
Clean Air ◽  
Beijing China

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.

scholarly journals Measurement report: Long-term changes in black carbon and aerosol optical properties from 2012 to 2020 in Beijing, China

2021 ◽  
Author(s):  
Jiaxing Sun ◽  
Zhe Wang ◽  
Wei Zhou ◽  
Conghui Xie ◽  
Cheng Wu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Black Carbon ◽  
Seasonal Variations ◽  
Radiative Forcing ◽  
Aerosol Optical Properties ◽  
Seasonal And Diurnal Variations ◽  
Long Term Changes ◽  
Clean Air ◽  
Beijing China

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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