Radiative Properties of Non-spherical Black Carbon Aerosols

Luo, Jie; Zhang, Qixing; Zhang, Yongming; Li, Zhengqiang

doi:10.1007/978-3-030-87683-8_3

Cited by 5 publications

(2 citation statements)

References 255 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Even if the coating materials are non‐absorbing, BC absorption may be enhanced by the “lens effect” when they coat on BC. Many studies have investigated the morphological effects of BC on the radiative properties, and BC absorption was found to be significantly affected by morphology (Kahnert & Kanngießer, 2020; Luo, Zhang, & Zhang, 2021; Luo, Zhang, Zhang, et al., 2021; Wu et al., 2018). However, the effects of BC microphysical properties on the aethalometer model were not analyzed in their studies.…”

Section: Introductionmentioning

confidence: 99%

The Simulated Source Apportionment of Light Absorbing Aerosols: Effects of Microphysical Properties of Partially‐Coated Black Carbon

Luo

Qiu

et al. 2023

JGR Atmospheres

Self Cite

View full text Add to dashboard Cite

Biomass burning (BB) fractions estimated with the aethalometer model differ from 0 even for pure aerosols from fossil fuel (FF) combustion. We used black carbon (BC) aerosols partially‐coated with non‐absorbing materials to represent typical FF aerosols, and the BB fractions were determined with the aethalometer model. Thus, the estimated BB fractions are the fractions that FF aerosols are incorrectly attributed to BB aerosols. The BC morphology and mixing state have significant effects on the estimation of BB fractions. For freshly emitted BC, the BB fractions do not deviate significantly from 0, and the BB fraction is generally in the range of −1%–10% based on an FF absorption Ångström exponent (AAE) of 1 and a BB AAE of 2. The BB fraction deviates substantially from 0 when BC becomes compact and is coated. The absolute values of the deviations sometimes can be close to 100% for heavily coated BC. The BB fraction is generally greater than 0 for fluffy BC while compact BC generally exhibits a negative BB fraction. The BB fractions of partially‐coated BC are very sensitive to the size distribution and coating ratio, which is consistent with the results of the core‐shell sphere model. We have also performed a series of studies with different configurations for BC morphologies, coating ratios, and mixing states, which show the variations of the estimated BB fractions with atmospheric aging. We also explain the reasons for the uncertainties in the BB fraction estimates and provide suggestions for using different AAE pairs.

show abstract

Section: Introductionmentioning

confidence: 99%

The Simulated Source Apportionment of Light Absorbing Aerosols: Effects of Microphysical Properties of Partially‐Coated Black Carbon

Luo

Qiu

et al. 2023

JGR Atmospheres

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, many studies have shown that BC particles, especially nascent ones, have fractal-like structures. The spherical assumption for BC can lead to a large deviation from the field measurement data and non-spherical simulated results (Chakrabarty et al, 2007;Luo et al, 2018cLuo et al, , 2021bHe et al, 2015;Liu and Mishchenko, 2005;Luo et al, 2018d;Mishchenko et al, 2016a). Based on the sampled BC images, researchers found that the shape of uncoated BC aggregates can be fitted well by a fractal law with monomer number (N s ), mean monomer radius (R), fractal prefactor (k 0 ), fractal dimension (D f ) and the radius of gyration (R g ) (Mishchenko et al, 2002;Sorensen, 2011;Luo et al, 2021a):…”

Section: Introductionmentioning

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.

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Advances in Atmospheric Radiation: Theories, Models, and Their Applications. Part I: Atmospheric Gas Absorption and Particle Scattering

Zhang,

Liu,

et al. 2024

J Meteorol Res

View full text Add to dashboard Cite

Radiative Properties of Non-spherical Black Carbon Aerosols

Cited by 5 publications

References 255 publications

The Simulated Source Apportionment of Light Absorbing Aerosols: Effects of Microphysical Properties of Partially‐Coated Black Carbon

The Simulated Source Apportionment of Light Absorbing Aerosols: Effects of Microphysical Properties of Partially‐Coated Black Carbon

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

Advances in Atmospheric Radiation: Theories, Models, and Their Applications. Part I: Atmospheric Gas Absorption and Particle Scattering

Contact Info

Product

Resources

About