Role of black carbon mass size distribution in the direct aerosol radiative forcing

Zhao, Gang; Tao, Jiangchuan; Kuang, Ye; Shen, Chuanyang; Yu, Yingli; Zhao, Chunsheng

doi:10.5194/acp-19-13175-2019

Cited by 34 publications

(35 citation statements)

References 70 publications

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“…The size distributions of the BC-containing aerosols exert significant influence on their corresponding radiative effects (Matsui et al, 2018;Zhao et al, 2019). We calculated the number size distribution (NSD) of BC-containing aerosols for the fresh and aged ones at different sites, and the results are shown in Fig.…”

Section: Size Distributions Of the Fresh And Aged Bc-containing Aerosolsmentioning

confidence: 99%

“…During the aging process, the BC optical properties change significantly up to a factor of 3 and then the corresponding magnitude of climate forcing contributed by BC is increased by up to a factor of 2 (Zhang et al, 2008;Cappa et al, 2012). Large uncertainties remain in estimating the BC radiative effects due to the large variation in BC microphysical properties, such as size distributions and mixing states during the aging process (Moffet et al, 2016;Matsui et al, 2018;Zhao et al, 2019). Therefore, characterizing the differences in size distributions and mixing states between the fresh and aged BC particles can help better constrain the uncertainties of BC aerosol radiative effects.…”

Section: Introductionmentioning

confidence: 99%

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Mixing state of refractory black carbon at different atmospheres in China

Zhao

Tan

et al. 2022

Preprint

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Abstract. Black carbon (BC) particles exert a significant influence on the earth's climate system. However, large uncertainties remain when estimating the radiative forcing by BC because the corresponding microphysical properties have not been well addressed. Knowleadge of the BC mixing states of different aging degree can help better characterise the corresponding environmental and climate effects. In this study, the BC size distributions were studied based on three different field campaigns at an urban site, a suburban site, and a background site in China using a single particle soot photometer (SP2) in tandem with a differential mobility diameter. Measurements from the SP2 indicate that the BC particles were composed of either fresh or aged aerosols. The mean number fractions of the fresh BC aerosols were 51 %, 67 %, and 21 % for the urban, suburban, and background sites, respectively. The corresponding mobility diameters of these aged (fresh) BC-containing aerosols were 294 nm (193 nm), 244 nm (161 (nm), and 257 nm (162 nm). The measured aged (fresh) BC core number median diameters were 115 nm (114 nm), 107 nm (95 nm), and 127 nm (111 nm) for urban, suburban, and background sites, respectively. The corresponding aged (fresh) core mass median diameters were 187 nm (154 nm), 182 nm (146 nm), and 238 nm (163 nm) respectively. The mean diameter of the aged BC-containing aerosols was larger than that of the fresh BC-containing aerosols, while the mean BC core diameter of the aged BC-containing aerosols was smaller than that of the fresh BC-containing aerosols. About 10 % of the BC-containing aerosols with the BC core were attached to the other non-BC components, which were mainly generated by coagulation between the BC and non-BC components. The measurement results in our study can help better understand the BC size distributions and mixing status in the different atmospheres in China and can be further used in modeling studies to help constrain the uncertainties of the BC radiative effects.

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Section: Size Distributions Of the Fresh And Aged Bc-containing Aerosolsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mixing state of refractory black carbon at different atmospheres in China

Zhao

Tan

et al. 2022

Preprint

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“…The loading and multi-scattering correction can thus be applied to the size-resolved particles. Other uncertainties may result from the low S/N ratio for the measured mono-dispersed particles, which can be largely improved by applying the fluctuation minimizing smoothing (FMS), which was applied for high-resolution measurements of mono-dispersed particles downstream of the DMA (Ran et al, 2016;Zhao et al, 2019). In addition, we compared the absorption coefficient measured from MA200 with a photoacoustic soot spectrometer (PASS-3, DMT) (Arnott et al, 2005), as shown in Figure S8.…”

Section: Measurementsmentioning

confidence: 99%

“…There may be uncertainties in the real refractive index (n) in deriving the optical diameter (Zhao et al, 2019), and n largely depends on the material density of the scattering particles (Liu & Daum, 2008). In this study, the mean material density of bulk aerosols is calculated from the ion balance with the assumed material density for each substance (Text S1, and Figure S3).…”

Section: The Determination Of Particle Dynamic Shape Factormentioning

confidence: 99%

“…The correction for the MA200 measurement followed a similar scenario, relating the BC mass fractions at each primary mobility size, as described previously (Deng et al, 2011;Zhao et al, 2019). The maximum number of charges on the particle is assumed to be 10, and the multiple charging function is transferred to compute the BC mass fraction for singly charged particles at each D m , calculated by the non-negative least square retrieval method based on a 10×1 vector and 10×10 matrix.…”

Section: Eliminating Multiply-charged Particlesmentioning

confidence: 99%

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Measurements of the Diversity of Shape and Mixing State for Ambient Black Carbon Particles

Kang

Liu

Tian

et al. 2021

Geophysical Research Letters

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Black carbon (BC) is an important light absorber (Bond & Bergstrom, 2006). Its optical properties are complicated by the complex particle morphology, such as the non-sphericity of the refractory BC (rBC) core (China et al., 2013), the amount of non-BC associated with it (termed as coatings) (Moffet & Prather, 2009;Zhang et al., 2008), and how the coatings and rBC components are combined (Liu et al., 2017). The conventional Mie calculation with the assumption of a core-shell structure may only apply to largely coated BC (Liu et al., 2017). However, it may exhibit a range of diversities when the amounts of coatings are not substantially higher than rBC (Fierce et al., 2020). The particle morphology of BC can be modified during aging (Akagi et al., 2012; and importantly determines the optimum optical models to be used (He, 2019). The inclusion of particle-resolved heterogeneity in the mixing state could induce an uncertainty of 30% in modeling the absorbing properties of BC (Fierce et al., 2016).The shape of non-spherical particles has been extensively studied based on the rule that a more irregular shape of a particle exerts a higher drag force than a sphere in an electric field, and a dynamic shape factor (χ) can be obtained by the ratio of the drag force on a non-spherical particle to its volume-equivalent sphere (Hinds, 1999). This is introduced to describe the particle shape in the form of electric mobility size

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