Calculations of the mass absorption cross sections for carbonaceous nanoparticles modeling soot

Fernández, C. García; Picaud, Sylvain; Devel, M.

doi:10.1016/j.jqsrt.2015.05.011

Cited by 21 publications

(19 citation statements)

References 57 publications

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“…m , shows an obvious dependency of the radiative properties on the exact value of m and also affects the wavelength-dependent evolution of the properties. Similarly, it has been reported in the literature that the effect of chemical composition of primary particle may have strong impact on the mass absorption cross section for the complete soot ensemble [50] . Q a was exponentially decreasing with increasing wavelength and shows a similar proportional relationship between Q a and ɑ eff .…”

Section: Small-scale Radiative Propertiessupporting

confidence: 70%

Optical characterization of multi-scale morphologically complex heterogeneous media – Application to snow with soot impurities

Dai

Haussener

2018

Journal of Quantitative Spectroscopy and Radiative Transfer

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a b s t r a c tA multi-scale methodology for the radiative transfer analysis of heterogeneous media composed of morphologically-complex components on two distinct scales is presented. The methodology incorporates the exact morphology at the various scales and utilizes volume-averaging approaches with the corresponding effective properties to couple the scales. At the continuum level, the volume-averaged coupled radiative transfer equations are solved utilizing ( i ) effective radiative transport properties obtained by direct Monte Carlo simulations at the pore level, and ( ii ) averaged bulk material properties obtained at particle level by Lorenz-Mie theory or discrete dipole approximation calculations. This model is applied to a soot-contaminated snow layer, and is experimentally validated with reflectance measurements of such layers. A quantitative and decoupled understanding of the morphological effect on the radiative transport is achieved, and a significant influence of the dual-scale morphology on the macroscopic optical behavior is observed. Our results show that with a small amount of soot particles, of the order of 1ppb in volume fraction, the reduction in reflectance of a snow layer with large ice grains can reach up to 77% (at a wavelength of 0.3 μm). Soot impurities modeled as compact agglomerates yield 2-3% lower reduction of the reflectance in a thick show layer compared to snow with soot impurities modeled as chain-like agglomerates. Soot impurities modeled as equivalent spherical particles underestimate the reflectance reduction by 2-8%. This study implies that the morphology of the heterogeneities in a media significantly affects the macroscopic optical behavior and, specifically for the soot-contaminated snow, indicates the non-negligible role of soot on the absorption behavior of snow layers. It can be equally used in technical applications for the assessment and optimization of optical performance in multi-scale media.

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Section: Small-scale Radiative Propertiessupporting

confidence: 70%

Optical characterization of multi-scale morphologically complex heterogeneous media – Application to snow with soot impurities

Dai

Haussener

2018

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…In this work, we focus on vertical distributions of aerosol absorption, measured with miniature absorption sensors on board small-and medium-sized UASs during two intensive field campaigns at contrasted locations in the eastern Mediterranean: an urban site (Athens, Greece) and a remote regional background site (Cyprus Atmospheric Observatory, CAO, Cyprus). The vertical distribution of aerosols in the eastern Mediterranean is of particular importance because it lies at the crossroads of diverse air masses (Lelieveld et al, 2002) carrying aerosol of different compositions, including mineral dust from Africa and the Middle East, pollution from Europe and the nearby Middle East, and marine aerosol (Erel et al, 2006;Gerasopoulos et al, 2007;Kalivitis et al, 2007). In addition, aerosol absorption measurements, whether ground or aerial based, are rather scarce in the region.…”

Section: Introductionmentioning

confidence: 99%

On-flight intercomparison of three miniature aerosol absorption sensors using unmanned aerial systems (UASs)

Pikridas

Bezantakos

Močnik³

et al. 2019

Atmos. Meas. Tech.

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Abstract. The present study investigates and compares the ground and in-flight performance of three miniaturized aerosol absorption sensors integrated on board small-sized Unmanned Aerial Systems (UASs). These sensors were evaluated during two contrasted field campaigns performed at an urban site, impacted mainly by local traffic and domestic wood burning sources (Athens, Greece), and at a remote regional background site, impacted by long-range transported sources including dust (Cyprus Atmospheric Observatory, Agia Marina Xyliatou, Cyprus). The miniaturized sensors were first intercompared at the ground-level against two commercially available instruments used as a reference. The measured signal of the miniaturized sensors was converted into the absorption coefficient and equivalent black carbon concentration (eBC). When applicable, signal saturation corrections were applied, following the suggestions of the manufacturers. The aerosol absorption sensors exhibited similar behavior against the reference instruments during the two campaigns, despite the diversity of the aerosol origin, chemical composition, sources, and concentration levels. The deviation from the reference during both campaigns concerning (eBC) mass was less than 8 %, while for the absorption coefficient it was at least 15 %. This indicates that those sensors that report black carbon mass are tuned and corrected to measure eBC more accurately than the absorption coefficient. The overall potential use of miniature aerosol absorption sensors on board small UASs is also illustrated. UAS-based absorption measurements were used to investigate the vertical distribution of eBC over Athens up to 1 km above sea level during January 2016, exceeding the top of the planetary boundary layer (PBL). Our results reveal a heterogeneous boundary layer concentration of absorbing aerosol within the PBL intensified in the early morning hours due to the concurrent peak traffic emissions at ground-level and the fast development of the boundary layer. After the full development of the PBL, homogenous concentrations are observed from 100 m a.g.l. to the PBL top.

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“…As pointed out by Michelsen et al [68] soot optical properties such as E(m(λ)) very much depend on soot maturity and thus chemical composition [32,66,69]. Moreover, the absorption properties also depend on the internal atomic structure of soot primary particles as highlighted by Fernandez et al [70]. We want to emphasize that the assumption of a constant E(m) used in this work is just one possible choice among many others with different variations over wavelength, yet still resulting in a continuous absorption spectrum.…”

Section: Contribution Of Sootmentioning

confidence: 98%

In situ characterisation of absorbing species in stationary premixed flat flames using UV–Vis absorption spectroscopy

2021

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A one-dimensional premixed ethylene–air flame is investigated regarding the presence of various combustion intermediates and products relevant for the formation of carbonaceous particles for various equivalence ratios and spatial positions using in situ UV–Vis absorption spectroscopy. A laser driven light source in combination with a fast spectrometer allow to record absorption spectra at a high rate required for practical combustion devices. The approach is coupled with a least squares regression procedure using a database of several absorbing species in the flame. To account for the high temperature flame conditions, the absorption spectra are convoluted by a simplified Maxwell–Boltzmann distribution model. While the approach is based on several assumptions and a verification requires future detailed intercomparison with other techniques, a first semi-quantitative evaluation can be obtained. This novel approach opens a potential route to the in situ measurement of the evolution of polycyclic aromatic hydrocarbons (PAHs) in flames.

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Calculations of the mass absorption cross sections for carbonaceous nanoparticles modeling soot

Cited by 21 publications

References 57 publications

Optical characterization of multi-scale morphologically complex heterogeneous media – Application to snow with soot impurities

Optical characterization of multi-scale morphologically complex heterogeneous media – Application to snow with soot impurities

On-flight intercomparison of three miniature aerosol absorption sensors using unmanned aerial systems (UASs)

In situ characterisation of absorbing species in stationary premixed flat flames using UV–Vis absorption spectroscopy

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