scholarly journals Broadband optical properties of biomass-burning aerosol and identification of brown carbon chromophores

2017 ◽  
Vol 122 (10) ◽  
pp. 5441-5456 ◽  
Author(s):  
Nir Bluvshtein ◽  
Peng Lin ◽  
J. Michel Flores ◽  
Lior Segev ◽  
Yinon Mazar ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Brown Carbon ◽  
Biomass Burning Aerosol

scholarly journals Modelling the optical properties of fresh biomass burning aerosol produced in a smoke chamber: results from the EFEU campaign

2007 ◽  
Vol 7 (4) ◽  
pp. 12657-12686 ◽  
Author(s):  
K. Hungershöfer ◽  
K. Zeromskiene ◽  
Y. Iinuma ◽  
G. Helas ◽  
J. Trentmann ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Absorption Efficiency ◽  
Max Planck ◽  
Fresh Biomass ◽  
Biomass Burning Aerosol ◽  
Smoke Chamber ◽  
The Impact ◽  
Mass Absorption Efficiency

Abstract. A better characterisation of the optical properties of biomass burning aerosol as a function of the burning conditions is required in order to quantify their effects on climate and atmospheric chemistry. Controlled laboratory combustion experiments with different fuel types were carried out at the combustion facility of the Max Planck Institute for Chemistry (Mainz, Germany) as part of the 'Impact of Vegetation Fires on the Composition and Circulation of the Atmosphere' (EFEU) project. Using the measured size distributions as well as mass scattering and absorption efficiencies, Mie calculations provided mean effective refractive indices of 1.60−0.010i and 1.56−0.010i (λ=0.55 μm) for smoke particles emitted from the combustion of savanna grass and an African hardwood (musasa), respectively. The relatively low imaginary parts suggest that the light-absorbing carbon of the investigated fresh biomass burning aerosol is only partly graphitized, resulting in strongly scattering and less absorbing particles. While the observed variability in mass scattering efficiencies was consistent with changes in particle size, the changes in the mass absorption efficiency can only be explained, if the chemical composition of the particles varies with combustion conditions.

scholarly journals Intercomparison of biomass burning aerosol optical properties from in situ and remote-sensing instruments in ORACLES-2016

2019 ◽  
Vol 19 (14) ◽  
pp. 9181-9208 ◽  
Author(s):  
Kristina Pistone ◽  
Jens Redemann ◽  
Sarah Doherty ◽  
Paquita Zuidema ◽  
Sharon Burton ◽  
...  
Keyword(s):  
Optical Properties ◽  
Case Studies ◽  
Biomass Burning ◽  
Radiative Forcing ◽  
Measurement Techniques ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Aerosol Optical Properties ◽  
Biomass Burning Aerosol

Abstract. The total effect of aerosols, both directly and on cloud properties, remains the biggest source of uncertainty in anthropogenic radiative forcing on the climate. Correct characterization of intensive aerosol optical properties, particularly in conditions where absorbing aerosol is present, is a crucial factor in quantifying these effects. The southeast Atlantic Ocean (SEA), with seasonal biomass burning smoke plumes overlying and mixing with a persistent stratocumulus cloud deck, offers an excellent natural laboratory to make the observations necessary to understand the complexities of aerosol–cloud–radiation interactions. The first field deployment of the NASA ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) campaign was conducted in September of 2016 out of Walvis Bay, Namibia. Data collected during ORACLES-2016 are used to derive aerosol properties from an unprecedented number of simultaneous measurement techniques over this region. Here, we present results from six of the eight independent instruments or instrument combinations, all applied to measure or retrieve aerosol absorption and single-scattering albedo. Most but not all of the biomass burning aerosol was located in the free troposphere, in relative humidities typically ranging up to 60 %. We present the single-scattering albedo (SSA), absorbing and total aerosol optical depth (AAOD and AOD), and absorption, scattering, and extinction Ångström exponents (AAE, SAE, and EAE, respectively) for specific case studies looking at near-coincident and near-colocated measurements from multiple instruments, and SSAs for the broader campaign average over the month-long deployment. For the case studies, we find that SSA agrees within the measurement uncertainties between multiple instruments, though, over all cases, there is no strong correlation between values reported by one instrument and another. We also find that agreement between the instruments is more robust at higher aerosol loading (AOD400>0.4). The campaign-wide average and range shows differences in the values measured by each instrument. We find the ORACLES-2016 campaign-average SSA at 500 nm (SSA500) to be between 0.85 and 0.88, depending on the instrument considered (4STAR, AirMSPI, or in situ measurements), with the interquartile ranges for all instruments between 0.83 and 0.89. This is consistent with previous September values reported over the region (between 0.84 and 0.90 for SSA at 550nm). The results suggest that the differences observed in the campaign-average values may be dominated by instrument-specific spatial sampling differences and the natural physical variability in aerosol conditions over the SEA, rather than fundamental methodological differences.

scholarly journals Chemical and optical properties of carbonaceous aerosols in Nanjing, eastern China: regionally transported biomass burning contribution

2019 ◽  
Vol 19 (17) ◽  
pp. 11213-11233 ◽  
Author(s):  
Xiaoyan Liu ◽  
Yan-Lin Zhang ◽  
Yiran Peng ◽  
Lulu Xu ◽  
Chunmao Zhu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Solar Energy ◽  
Energy Absorption ◽  
Biomass Burning ◽  
Eastern China ◽  
Water Soluble ◽  
Carbonaceous Aerosols ◽  
Southeastern China ◽  
Brown Carbon

Abstract. Biomass burning can significantly impact the chemical and optical properties of carbonaceous aerosols. Here, the biomass burning impacts were studied during wintertime in a megacity of Nanjing, eastern China. The high abundance of biomass burning tracers such as levoglucosan (lev), mannosan (man), galactosan (gal) and non-sea-salt potassium (nss-K+) was found during the studied period with the concentration ranges of 22.4–1476 ng m−3, 2.1–56.2 ng m−3, 1.4–32.2 ng m−3 and 0.2–3.8 µg m−3, respectively. The significant contribution of biomass burning to water-soluble organic carbon (WSOC; 22.3±9.9 %) and organic carbon (OC; 20.9±9.3 %) was observed in this study. Backward air mass origin analysis, potential emission sensitivity of elemental carbon (EC) and MODIS fire spot information indicated that the elevations of the carbonaceous aerosols were due to the transported biomass-burning aerosols from southeastern China. The characteristic mass ratio maps of lev∕man and lev∕nss-K+ suggested that the biomass fuels were mainly crop residuals. Furthermore, the strong correlation (p < 0.01) between biomass burning tracers (such as lev) and light absorption coefficient (babs) for water-soluble brown carbon (BrC) revealed that biomass burning emissions played a significant role in the light-absorption properties of carbonaceous aerosols. The solar energy absorption due to water-soluble brown carbon and EC was estimated by a calculation based on measured light-absorbing parameters and a simulation based on a radiative transfer model (RRTMG_SW). The solar energy absorption of water-soluble BrC in short wavelengths (300–400 nm) was 0.8±0.4 (0.2–2.3) W m−2 (figures in parentheses represent the variation range of each parameter) from the calculation and 1.2±0.5 (0.3–1.9) W m−2 from the RRTMG_SW model. The absorption capacity of water-soluble BrC accounted for about 20 %–30 % of the total absorption of EC aerosols. The solar energy absorption of water-soluble BrC due to biomass burning was estimated as 0.2±0.1 (0.0–0.9) W m−2, considering the biomass burning contribution to carbonaceous aerosols. Potential source contribution function model simulations showed that the solar energy absorption induced by water-soluble BrC and EC aerosols was mostly due to the regionally transported carbonaceous aerosols from source regions such as southeastern China. Our results illustrate the importance of the absorbing water-soluble brown carbon aerosols in trapping additional solar energy in the low-level atmosphere, heating the surface and inhibiting the energy from escaping the atmosphere.

scholarly journals The characteristics of atmospheric brown carbon in Xi'an, inland China: sources, size distributions and optical properties

2020 ◽  
Vol 20 (4) ◽  
pp. 2017-2030 ◽  
Author(s):  
Can Wu ◽  
Gehui Wang ◽  
Jin Li ◽  
Jianjun Li ◽  
Cong Cao ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Urban Atmosphere ◽  
Semiarid Region ◽  
Chemical Compositions ◽  
Brown Carbon ◽  
Polycyclic Aromatic ◽  
Fine Mode

Abstract. To investigate the characteristics of atmospheric brown carbon (BrC) in the semiarid region of East Asia, PM2.5 and size-resolved particles in the urban atmosphere of Xi'an, inland China, during the winter and summer of 2017 were collected and analyzed for optical properties and chemical compositions. Methanol extracts (MeOH extracts) were more light-absorbing than water extracts (H2O extracts) in the optical wavelength of 300–600 nm and well correlated with nitrophenols, polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (r > 0.78). The light absorptions (absλ=365 nm) of H2O extracts and MeOH extracts in winter were 28±16 and 49±32 M m−1, respectively, which are about 10 times higher than those in summer, mainly due to the enhanced emissions from biomass burning for house heating. Water-extracted BrC predominately occurred in the fine mode (< 2.1 µm) during winter and summer, accounting for 81 % and 65 % of the total absorption of BrC, respectively. The light absorption and stable carbon isotope composition measurements showed an increasing ratio of absλ=365 nm-MeOH to absλ=550 nm-EC along with an enrichment of 13C in PM2.5 during the haze development, indicating an accumulation of secondarily formed BrC (e.g., nitrophenols) in the aerosol aging process. Positive matrix factorization (PMF) analysis showed that biomass burning, fossil fuel combustion, secondary formation, and fugitive dust are the major sources of BrC in the city, accounting for 55 %, 19 %, 16 %, and 10 % of the total BrC of PM2.5, respectively.

scholarly journals Parameterization of single-scattering albedo (SSA) and absorption Ångström exponent (AAE) with EC / OC for aerosol emissions from biomass burning

2016 ◽  
Vol 16 (15) ◽  
pp. 9549-9561 ◽  
Author(s):  
Rudra P. Pokhrel ◽  
Nick L. Wagner ◽  
Justin M. Langridge ◽  
Daniel A. Lack ◽  
Thilina Jayarathne ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Single Scattering ◽  
Emission Factors ◽  
Single Scattering Albedo ◽  
Biomass Fuels ◽  
Brown Carbon ◽  
Pearson's R ◽  
Biomass Burning Aerosol ◽  
Pearson’S R

Abstract. Single-scattering albedo (SSA) and absorption Ångström exponent (AAE) are two critical parameters in determining the impact of absorbing aerosol on the Earth's radiative balance. Aerosol emitted by biomass burning represent a significant fraction of absorbing aerosol globally, but it remains difficult to accurately predict SSA and AAE for biomass burning aerosol. Black carbon (BC), brown carbon (BrC), and non-absorbing coatings all make substantial contributions to the absorption coefficient of biomass burning aerosol. SSA and AAE cannot be directly predicted based on fuel type because they depend strongly on burn conditions. It has been suggested that SSA can be effectively parameterized via the modified combustion efficiency (MCE) of a biomass burning event and that this would be useful because emission factors for CO and CO2, from which MCE can be calculated, are available for a large number of fuels. Here we demonstrate, with data from the FLAME-4 experiment, that for a wide variety of globally relevant biomass fuels, over a range of combustion conditions, parameterizations of SSA and AAE based on the elemental carbon (EC) to organic carbon (OC) mass ratio are quantitatively superior to parameterizations based on MCE. We show that the EC ∕ OC ratio and the ratio of EC ∕ (EC + OC) both have significantly better correlations with SSA than MCE. Furthermore, the relationship of EC ∕ (EC + OC) with SSA is linear. These improved parameterizations are significant because, similar to MCE, emission factors for EC (or black carbon) and OC are available for a wide range of biomass fuels. Fitting SSA with MCE yields correlation coefficients (Pearson's r) of  ∼  0.65 at the visible wavelengths of 405, 532, and 660 nm while fitting SSA with EC / OC or EC / (EC + OC) yields a Pearson's r of 0.94–0.97 at these same wavelengths. The strong correlation coefficient at 405 nm (r =  0.97) suggests that parameterizations based on EC / OC or EC / (EC + OC) have good predictive capabilities even for fuels in which brown carbon absorption is significant. Notably, these parameterizations are effective for emissions from Indonesian peat, which have very little black carbon but significant brown carbon (SSA  =  0.990 ± 0.001 at 532 and 660 nm, SSA  =  0.937 ± 0.011 at 405 nm). Finally, we demonstrate that our parameterization based on EC / (EC + OC) accurately predicts SSA during the first few hours of plume aging with data from Yokelson et al. (2009) gathered during a biomass burning event in the Yucatán Peninsula of Mexico.

scholarly journals Molecular Characterization of Brown Carbon in Biomass Burning Aerosol Particles

2016 ◽  
Vol 50 (21) ◽  
pp. 11815-11824 ◽  
Author(s):  
Peng Lin ◽  
Paige K. Aiona ◽  
Ying Li ◽  
Manabu Shiraiwa ◽  
Julia Laskin ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Biomass Burning ◽  
Aerosol Particles ◽  
Brown Carbon ◽  
Biomass Burning Aerosol

scholarly journals Measurement Report: Optical properties and sources of water-soluble brown carbon in Tianjin, North China: insights from organic molecular compositions

2022 ◽  
Author(s):  
Junjun Deng ◽  
Hao Ma ◽  
Xinfeng Wang ◽  
Shujun Zhong ◽  
Zhimin Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Light Absorption ◽  
Radiative Forcing ◽  
North China ◽  
Water Soluble ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Brown Carbon ◽  
Near Ultraviolet

Abstract. Brown carbon (BrC) aerosols exert vital impacts on climate change and atmospheric photochemistry due to their light absorption in the wavelength range from near-ultraviolet (UV) to visible light. However, the optical properties and formation mechanisms of ambient BrC remain poorly understood, limiting the estimation of their radiative forcing. In the present study, fine aerosols (PM2.5) were collected during 2016–2017 on a day/night basis over urban Tianjin, a megacity in North China, to obtain seasonal and diurnal patterns of atmospheric water-soluble BrC. There were obvious seasonal but no evident diurnal variations in light absorption properties of BrC. In winter, BrC showed much stronger light absorbing ability since mass absorption efficiency at 365 nm (MAE365) (1.54 ± 0.33 m2 g−1), which was 1.8 times larger than that (0.84 ± 0.22 m2 g−1) in summer. Direct radiative effects by BrC absorption relative to black carbon in the UV range were 54.3 ± 16.9 % and 44.6 ± 13.9 %, respectively. In addition, five fluorescent components in BrC, including three humic-like fluorophores and two protein-like fluorophores were identified with excitation-emission matrix fluorescence spectrometry and parallel factor (PARAFAC) analysis. The lowly-oxygenated components contributed more to winter and nighttime samples, while more-oxygenated components increased in summer and daytime samples. The higher humification index (HIX) together with lower biological index (BIX) and fluorescence index (FI) suggest that the chemical compositions of BrC were associated with a high aromaticity degree in summer and daytime due to photobleaching. Fluorescent properties indicate that wintertime BrC were predominantly affected by primary emissions and fresh secondary organic aerosol (SOA), while summer ones were more influenced by aging processes. Results of source apportionments using organic molecular compositions of the same set of aerosols reveal that fossil fuel combustion and aging processes, primary bioaerosol emission, biomass burning, and biogenic and anthropogenic SOA formation were the main sources of BrC. Biomass burning contributed much larger to BrC in winter and at nighttime, while biogenic SOA contributed more in summer and at daytime. Especially, our study highlights that primary bioaerosol emission is an important source of BrC in urban Tianjin in summer.

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