Method to measure the size-resolved real part of aerosol refractive index using differential mobility analyzer in tandem with single-particle soot photometer

Zhao, Gang; Zhao, Wenrui; Zhao, Chunsheng

doi:10.5194/amt-12-3541-2019

Cited by 16 publications

(5 citation statements)

References 46 publications

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“…The size-resolved BC core distribution and non-BC coating thickness were measured using a differential mobility analyzer (DMA, model 3081, TSI, USA) in tandem with a single-particle soot photometer (SP2, Droplet Measurement Technologies, USA). For detailed information on the DMA, the reader is referred to Zhao et al (2019c). SP2 can measure the BC mass concentration from the incandescence signals emitted by the BC particle, which is heated to around 6000 K by a laser with a wavelength of 1064 nm (Zhao et al, 2020b).…”

Section: Field Measurementsmentioning

confidence: 99%

“…The coating materials are also critical in regulating the morphology and optical properties as the coating of sulfuric acid has been shown to be more efficient in altering the BC morphology and light absorption (Zhang et al, 2008;Xue et al, 2009b, a). Zhao et al (2019b) reported that the light absorption properties of ambient BC particles are influenced by BC mass size distribution. In addition, recently, researchers have found that the E abs values are also controlled by particle-to-particle heterogeneity (Fierce et al, 2016(Fierce et al, , 2020.…”

Section: Introductionmentioning

confidence: 99%

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Method to quantify black carbon aerosol light absorption enhancement with a mixing state index

et al. 2021

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Abstract. Large uncertainties remain when estimating the warming effects of ambient black carbon (BC) aerosols on climate. One of the key challenges in modeling the radiative effects is predicting the BC light absorption enhancement, which is mainly determined by the mass ratio (MR) of non-BC coating material to BC in the population of BC-containing aerosols. For the same MR, recent research has found that the radiative absorption enhancements by BC are also controlled by its particle-to-particle heterogeneity. In this study, the BC mixing state index (χ) is developed to quantify the dispersion of ambient black carbon aerosol mixing states based on binary systems of BC and other non-black carbon components. We demonstrate that the BC light absorption enhancement increases with χ for the same MR, which indicates that χ can be employed as a factor to constrain the light absorption enhancement of ambient BC. Our framework can be further used in the model to study the radiative effects of black carbon on climate change.

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Section: Field Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Method to quantify black carbon aerosol light absorption enhancement with a mixing state index

et al. 2021

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“…The range of the measured RRI (1.34-1.56) is a little wider than the literature values. Past measurements of ambient aerosol RRI values vary between 1.4 and 1.6 (Dubovik, 2002;Guyon et al, 2003;Zhang et al, 2016) over a different measurement site. This is the first time that such high variations in ambient aerosol RRI have been observed at one site.…”

Section: Measurement Resultsmentioning

confidence: 99%

A new parameterization scheme for the real part of the ambient urban aerosol refractive index

et al. 2019

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Abstract. The refractive index of ambient aerosols, which directly determines the aerosol optical properties, is widely used in atmospheric models and remote sensing. Traditionally, the real part of the refractive index (RRI) is parameterized by the measurement of ambient aerosol main inorganic components. In this paper, the characteristics of the ambient aerosol RRI are studied based on field measurements in East China. The results show that the measured ambient aerosol RRI varies significantly between 1.36 and 1.56. The direct aerosol radiative forcing is estimated to vary by 40 % when the RRI values were varied between 1.36 and 1.56. We find that the ambient aerosol RRI is highly correlated with the aerosol effective density (ρeff) rather than the main chemical components. However, the parameterization of the ambient aerosol RRI by ρeff is not available due to the lack of corresponding simultaneous field measurements. For the first time, the size-resolved ambient aerosol RRI and ρeff are measured simultaneously by our designed measurement system. A new parameterization scheme for the ambient aerosol RRI using ρeff is proposed for urban environments. The measured and parameterized RRI values agree well, with a correlation coefficient of 0.75 and slope of 0.99. Knowledge of the ambient aerosol RRI would improve our understanding of ambient aerosol radiative effects.

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“…The refractive index of the core adopted here is 1.67+0.67i, which is the calculated mean value by comparing the measured light absorption and calculated light absorption properties (Zhao et al, 2020a). The refractive index of the shell is chosen to be 1.46+0i, which is 100 assumed to be as that of the non-BC component measured by the DMA-SP2 system (Zhao et al,101 2019a; Zhao et al, 2019c). With the above information, the σ values at a given Dp and a given Dc .…”

Section: Calculating the Aerosol Absorption Coefficient For A Given Dmentioning

confidence: 99%

Method to Quantify the Black Carbon Aerosol Light Absorption Enhancement with Entropy and Diversity Measures

Zhao¹,

Tan²,

Zhu³

et al. 2021

Preprint

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Abstract. Large uncertainties remain when estimating the warming effects of ambient black carbon (BC) aerosols on climate. One of the key challenges in modeling the radiative effects is predicting the BC light absorption enhancement, which is mainly determined by its mass ratio of non-BC coating thickness to BC (MR). For the same MR, recent researches find that the radiative absorption enhancements by BC are also controlled by its particle-to-particle heterogeneity. In this study, the BC mixing state index (χ) is developed to quantify the dispersion of ambient black carbon aerosol mixing states based on binary systems of BC and other non-black carbon components. We demonstrate that the BC light absorption enhancement increases with χ for the same MR, which indicates that χ can be employed as a factor to constrain the light absorption enhancement of ambient BC. Our framework can be further used in the model to study the black carbon radiative effects on climate change.

show abstract

Method to measure the size-resolved real part of aerosol refractive index using differential mobility analyzer in tandem with single-particle soot photometer

Cited by 16 publications

References 46 publications

Method to quantify black carbon aerosol light absorption enhancement with a mixing state index

Method to quantify black carbon aerosol light absorption enhancement with a mixing state index

A new parameterization scheme for the real part of the ambient urban aerosol refractive index

Method to Quantify the Black Carbon Aerosol Light Absorption Enhancement with Entropy and Diversity Measures

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