Aerosol clustering in an urban environment of Beijing during (2005–2017)

Shaheen, Kausar; Shah, Zarbad; Suo, Hongli; Liu, Min; Ma, Lin; Alam, Khan; Gul, Alia; Cui, Jinli; Li, Chunyan; Ya, Wang; Khan, Shahid Ali; Khan, Sher Bahadar

doi:10.1016/j.atmosenv.2019.06.027

Cited by 10 publications

(4 citation statements)

References 77 publications

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“…Figure 10 shows the comparison of SSA using different BC models. Shin et al (2019b) showed that the mean SSA at 440 nm was approximately 0.89-0.92 in Beijing using AERONET data, and Shaheen et al (2019) demonstrated that the mean SSA at 440 nm was approximately 0.897 in winter Beijing. At 450 nm, the calculated SSA in typical urban cities is within the range of 0.86-0.92, which is generally consistent with the observations in previous studies.…”

Section: Impacts Of Bc Morphology On Aod and Aaodmentioning

confidence: 99%

Regional impacts of black carbon morphologies on shortwave aerosol–radiation interactions: a comparative study between the US and China

Luo

Zhang

et al. 2022

Atmos. Chem. Phys.

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Abstract. Black carbon (BC) is one of the dominant absorbing aerosol species in the atmosphere. It normally has complex fractal-like structures due to the aggregation process during combustion. A wide range of aerosol–radiation interactions (ARIs) of BC have been reported throughout experimental and modeling studies. One reason for the large discrepancies among multiple studies is the application of the oversimplified spherical morphology for BC in ARI estimates. In current climate models, the Mie theory is commonly used to calculate the optical properties of spherical BC aerosols. Here, we employ a regional chemical transport model coupled with a radiative transfer code that utilizes the non-spherical BC optical simulations to re-evaluate the effects of particles' morphologies on BC shortwave ARI, and the wavelength range of 0.3–4.0 µm was considered. Anthropogenic activities and wildfires are two major sources of BC emissions. Therefore, we choose the typical polluted area in eastern China, which is dominated by anthropogenic emissions, and the fire region in the northwest US, which is dominated by fire emissions in this study. A 1-month simulation in eastern China and a 7 d simulation in the fire region in the northwest US were performed. The fractal BC model generally presents a larger clear-sky ARI compared to the spherical BC model. Assuming BC particles are externally mixed with other aerosols, the relative differences in the time-averaged clear-sky ARI between the fractal model with a fractal dimension (Df) of 1.8 and the spherical model are 12.1 %–20.6 % and 10.5 %–14.9 % for typical polluted urban cities in China and fire sites in the northwest US, respectively. Furthermore, the regional-mean clear-sky ARI is also significantly affected by the BC morphology, and relative differences of 17.1 % and 38.7 % between the fractal model with a Df of 1.8 and the spherical model were observed in eastern China and the northwest US, respectively. However, the existence of clouds would weaken the BC morphological effects. The time-averaged all-sky ARI relative differences between the fractal model with a Df of 1.8 and the spherical model are 4.9 %–6.4 % and 9.0 %–11.3 % in typical urban polluted cities and typical fire sites, respectively. Besides, for the regional-mean all-sky ARI, the relative differences between the fractal model and the spherical model are less than 7.3 % and 16.8 % in the polluted urban area in China and the fire region in the US, respectively. The results imply that current climate modeling may significantly underestimate the BC ARI uncertainties as the morphological effects on BC ARI are ignored in most climate models.

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Section: Impacts Of Bc Morphology On Aod and Aaodmentioning

confidence: 99%

Regional impacts of black carbon morphologies on shortwave aerosol–radiation interactions: a comparative study between the US and China

Luo

Zhang

et al. 2022

Atmos. Chem. Phys.

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“…Figure 12 shows the EAE calculated using different BC models. By using AERONET observation data, in Beijing, Shaheen et al (2019) showed that the mean EAE at 440 -870 nm in winter was approximately 1.06 ± 0.36.…”

Section: Impacts Of Bc Morphology On Aae and Eaementioning

confidence: 99%

“…Figure 14 shows the comparison of SSA using different BC models. By using AERONET data, Shin et al (2019b) showed the mean SSA at 440 nm was approximately 0.89 -0.92 in Beijing, and Shaheen et al (2019) demonstrated mean SSA at 440 nm was approximately 0.897 in winter in Beijing.…”

Section: Impacts Of Bc Morphology On Ssamentioning

confidence: 99%

Regional impacts of black carbon morphologies on aerosol-radiation interactions: A comparative study between the US and China

Luo

Zhang

et al. 2022

Preprint

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Abstract. Black carbon (BC) is one of the dominant absorbing aerosol species in the atmosphere. It normally has complex fractal-like structures due to the aggregation process during combustion. A wide range of aerosol-radiation interactions (ARI) of BC has been reported throughout experimental and modeling studies. One reason for the large discrepancies among multiple studies is the application of the over-simplified spherical morphology for BC in ARI estimates. Here, we employ a regional chemical transport model coupled with a radiative transfer code which utilizes the non-spherical BC optical simulations to re-evaluate the effects of particles' morphologies on BC ARI. Anthropogenic activities and wildfires are two major sources of BC emissions. Therefore, we choose four typical polluted cities in East China which are dominated by urban emissions, and three locations in the northwest US that are dominated by fire emissions in this study. Our modeling results show that spherical BC models overestimate the aerosol optical depth (AOD) at 550 nm wavelength up to 0.03 and 0.15 at typical polluted cities in East China and fire regions in the northwest US, respectively, than fractal BC models with a fractal dimension (Df) of 1.8. Besides, spherical BC model underestimates BC aerosol absorption optical depth (AAOD) at 450 nm up to 0.016 and 0.04 at typical polluted cities in East China and fire sites in the US, respectively, than the fractal BC model. BC morphologies have relatively small impacts on the single scattering albedo (SSA) and extinction Ångström exponent (EAE), while these morphological effects on the absorption Ångström exponent (AAE) are rather significant. The spherical BC models underestimate AAE by approximately 0.17 at 450 and 850 nm wavelength pair than the fractal counterparts. Besides, BC morphologies have non-negligible impacts on the BC ARI. The calculated mean ARI using the spherical BC model is approximately 3.47–4.45 Wm−2 at typical polluted cities in China, while the values increase to approximately 3.83–4.92 Wm−2 when using the fractal aggregate model, and the relative variations are approximately 10.4 %–15.3 %. The mean BC ARI increases from approximately 4.91–6.61 Wm−2 to 5.52–7.05 Wm−2 and the relative variations for BC ARI are approximately 6.2 %–6.9 % when we modify the BC from spheres to fractal aggregates with a Df of 1.8 in the northwest US. Therefore, the effects of BC morphologies on the regional radiative effects should be carefully evaluated in different regions.

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“…The proportion of woodland increased from 25.05%, in 2015, to 28.71%, in 2018 (an increase of 3.65%); and among the various types of grasslands, the growth in high coverage grassland is the most prominent-where the proportion of total land area increased from 6.45% to 6.61% (an increase of 0.15%). The increase in the proportions of woodland and high coverage grassland could help reduce the carbon dioxide content in the atmosphere and lessen the greenhouse effect, which also plays a role in air purification and climate adjustment, and helps alleviate the pressure on the environment brought by the continuous development and increasingly concentrated population of Beijing [54][55][56][57]. In addition, the proportion of rivers and lakes, as well as that of reservoirs and ponds, have also increased in Beijing-increasing by 0.34% and 0.18%, respectively, in 2018, compared to figures from 2015.…”

Section: Beijingmentioning

confidence: 99%

Analysis and Prediction of Land Use in Beijing-Tianjin-Hebei Region: A Study Based on the Improved Convolutional Neural Network Model

Liu

Yang

et al. 2020

Sustainability

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During the rapid economic development of China, there are certain blind decisions made in the use of land resources, which poses a significant threat to sustainable development. With the help of the improved convolutional neural network model, this paper analyzes the land use of the Beijing-Tianjin-Hebei region of China from 1995 to 2018, and provides a prediction for 2023. The research results show that: (1) There is still much room for improvement in the land use of the Beijing-Tianjin-Hebei region, with dry land taking up the largest proportion of land in these three locations; (2) Beijing’s development has been well protected in terms of land use. It is predicted that by 2023, the proportions of its woodland, grassland, and rivers, lakes, reservoirs and ponds would increase by 0.26%, 0.30%, and 0.61%, respectively, compared with their proportion in 2018; (3) the land use type in Tianjin during the research period was generally stable. In 2018, the proportion of its woodland and grassland had increased by 1.04% and 0.61%, respectively, compared with that of 1995; and (4) many ecological and environmental problems were exposed during the construction of highways in Hebei province. The area of sand land, saline-alkali land, marshland, bare land, and bare rock areas have all increased, and their total proportion is predicted to reach 1.48% by 2023.

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Aerosol clustering in an urban environment of Beijing during (2005–2017)

Cited by 10 publications

References 77 publications

Regional impacts of black carbon morphologies on shortwave aerosol–radiation interactions: a comparative study between the US and China

Regional impacts of black carbon morphologies on shortwave aerosol–radiation interactions: a comparative study between the US and China

Regional impacts of black carbon morphologies on aerosol-radiation interactions: A comparative study between the US and China

Analysis and Prediction of Land Use in Beijing-Tianjin-Hebei Region: A Study Based on the Improved Convolutional Neural Network Model

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