Optical closure experiments for biomass smoke aerosols

Mack, Laura; Levin, Ezra J. T.; Kreidenweis, Sonia M.; Obrist, Daniel; Moosmüller, Hans; Lewis, K.; Arnott, W. P.; McMeeking, G. R.; Sullivan, A.; Wold, Cyle; Hao, Wei Min; Collett, Jeffrey L.; Malm, William C.

doi:10.5194/acp-10-9017-2010

Cited by 54 publications

(61 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The differences in SSA among biomass burning aerosols is likely explained by observed differences in combustion conditions generated by different fuel types, humidities, etc. as well as plume age (Reid and Hobbs, 1998;Eck et al, 2003;Kirchstetter et al, 2004;Chen et al, 2006;Lewis et al, 2008;Mack et al, 2010). For instance, in recent laboratory studies, the combustion of 14 different types of biomass fuel yielded a range in SSA 0.37-0.95 (Lewis et al, 2008;Mack et al, 2010).…”

Section: Ssa Retrievalmentioning

confidence: 99%

“…An SSA range of 0.5-1.0 was used to represent the wide range in SSA for biomass burning aerosols found in the literature (e.g., Bergstrom et al, 2003;Johnson et al, 2008;Lewis et al, 2008;Eck et al, 2009;Mack et al, 2010;Alados-Arboledas et al, 2011;Tesche et al, 2011). The differences in SSA among biomass burning aerosols is likely explained by observed differences in combustion conditions generated by different fuel types, humidities, etc.…”

Section: Ssa Retrievalmentioning

confidence: 99%

See 1 more Smart Citation

Spectral absorption of biomass burning aerosol determined from retrieved single scattering albedo during ARCTAS

et al. 2012

View full text Add to dashboard Cite

show abstract

Section: Ssa Retrievalmentioning

confidence: 99%

Section: Ssa Retrievalmentioning

confidence: 99%

Spectral absorption of biomass burning aerosol determined from retrieved single scattering albedo during ARCTAS

et al. 2012

View full text Add to dashboard Cite

show abstract

“…distributions (e.g., Liu and Daum, 2000;Mack et al, 2010). The solution of this inverse light-scattering problem is commonly achieved through iterative schemes, where the difference between measured and calculated optical properties is minimized.…”

Section: E Kassianov Et Al: Simultaneous Retrieval Of Effective Refmentioning

confidence: 99%

“…Calculate modeled optical properties from combined size distribution. Next we apply a technique similar to the optical closure methods (e.g., Liu and Daum, 2000;Mack et al, 2010) by using the particle number size distributions found in step (1) above, and Mie theory, to calculate modeled optical properties σ s,mod and β mod (Fig. 1b, c); here the subscript "mod" refers to calculated, modeled quantities.…”

Section: Approachmentioning

confidence: 99%

Simultaneous retrieval of effective refractive index and density from size distribution and light-scattering data: weakly absorbing aerosol

et al. 2014

View full text Add to dashboard Cite

Abstract. We propose here a novel approach for retrieving in parallel the effective density and real refractive index of weakly absorbing aerosol from optical and size distribution measurements. Here we define "weakly absorbing" as aerosol single-scattering albedos that exceed 0.95 at 0.5 µm. The required optical measurements are the scattering coefficient and the hemispheric backscatter fraction, obtained in this work from an integrating nephelometer. The required size spectra come from mobility and aerodynamic particle size spectrometers commonly referred to as a scanning mobility particle sizer and an aerodynamic particle sizer. The performance of this approach is first evaluated using a sensitivity study with synthetically generated but measurementrelated inputs. The sensitivity study reveals that the proposed approach is robust to random noise; additionally the uncertainties of the retrieval are almost linearly proportional to the measurement errors, and these uncertainties are smaller for the real refractive index than for the effective density. Next, actual measurements are used to evaluate our approach. These measurements include the optical, microphysical, and chemical properties of weakly absorbing aerosol which are representative of a variety of coastal summertime conditions observed during the Two-Column Aerosol Project (TCAP; http://campaign.arm.gov/tcap/). The evaluation includes calculating the root mean square error (RMSE) between the aerosol characteristics retrieved by our approach, and the same quantities calculated using the conventional volume mixing rule for chemical constituents. For dry conditions (defined in this work as relative humidity less than 55 %) and sub-micron particles, a very good (RMSE ∼ 3 %) and reasonable (RMSE ∼ 28 %) agreement is obtained for the retrieved real refractive index (1.49 ± 0.02) and effective density (1.68 ± 0.21), respectively. Our approach permits discrimination between the retrieved aerosol characteristics of sub-micron and sub-10-micron particles. The evaluation results also reveal that the retrieved density and refractive index tend to decrease with an increase of the relative humidity.

show abstract

“…While the optical properties of BB aerosols produced by several North American biomass fuels have been and are being investigated, both in the laboratory and in field campaigns (Hodzic et al, 2007;Yokelson et al, 2009;Liu et al, 2014;McMeeking et al, 2009;Levin et al, 2010;Mack, 2008;Mack et al, 2010), BB aerosols for sub-Saharan African fuels were only investigated in field 45 studies Formenti et al, 2003). To our knowledge, there have not been any laboratory studies of the optical properties of BB aerosols from fuels sources common in sub-Saharan Africa.…”

mentioning

confidence: 99%

Construction and Characterization of an Indoor Smog Chamber for the Measurement of the Optical and Physicochemical Properties of Aging Biomass Burning Aerosols Native to sub-Saharan Africa

Smith

Fiddler

Sexton

et al. 2018

Preprint

View full text Add to dashboard Cite

Abstract. We describe here the construction and characterization of a new smog chamber facility (NCAT chamber) for studying the chemical and optical properties of biomass burning (BB) aerosols from biomass fuels native to sub-Saharan Africa. This facility is comprised of a ~9 m 3 fluorinated ethylene propylene film (FEP) reactor placed in a temperature-controlled room and coupled with a cavity ring-down spectrometer, nephelometer, condensation particle counter, differential mobility analyzer and other analytical instruments, such as NO X and O 3 20 analyzers, a GC, a filter sampler, and an impinger for collecting particles in water. Construction details and characterization experiments are described, including measurements of BB particulate size distribution and deposition rate, gas wall loss rates, dilution rate, light intensity, mixing speed, temperature and humidity variations, and air purification method. The wall loss rates for NO, NO 2 , and O 3 were found to be (7.40 ± 0.01) × 10 −4 , (3.47 ± 0.01) × 10 −4 , and (5.90 ± 0.08) × 10 −4 min −1 respectively. The NO 2 photolysis rate constant was 0.165 ±0.005 min -1 , 25 which corresponds to a flux of (7.72 ± 0.25) × 10 17 photons•nm•cm −2 •s −1 from 296.0−516.8 nm. Particle deposition rate was found to be (2.46 ± 0.11) x 10 −3 min −1 for pine at D p = 100 nm. After initial mixing in the chamber, with the ultraviolet (UV) light off, the particle size distribution for BB samples used for the initial work did not stabilize until ~7.5 hours after injection peaking near a mobility diameter of ~340 nm. The chamber demonstrated gas and particle loss rates, and other properties comparable to other similar indoor smog chambers 30

show abstract

Optical closure experiments for biomass smoke aerosols

Cited by 54 publications

References 35 publications

Spectral absorption of biomass burning aerosol determined from retrieved single scattering albedo during ARCTAS

Spectral absorption of biomass burning aerosol determined from retrieved single scattering albedo during ARCTAS

Simultaneous retrieval of effective refractive index and density from size distribution and light-scattering data: weakly absorbing aerosol

Construction and Characterization of an Indoor Smog Chamber for the Measurement of the Optical and Physicochemical Properties of Aging Biomass Burning Aerosols Native to sub-Saharan Africa

Contact Info

Product

Resources

About