Laboratory measurements of the optical properties of sea salt aerosol

Abstract. The extinction spectra of laboratory generated sea salt aerosols have been measured from 1 μm to 20 μm using a Bruker 66v/S FTIR spectrometer. Concomitant measurements include temperature, pressure, relative humidity and the aerosol size distribution. The refractive indices of the sea salt aerosol have been determined using a simple harmonic oscillator band model (Thomas et al., 2004) for aerosol with relative humidities at eight different values between 0.4% to 86%. The resulting refractive index spectra show significant discrepancies when compared to existing sea salt refractive indices calculated using volume mixing rules (Shettle and Fenn, 1979). Specifically, an additional band is found in the refractive indices of dry sea salt aerosol and the new data shows increased values of refractive index at almost all wavelengths. This implies that the volume mixing rules, currently used to calculate the refractive indices of wet sea salt aerosols, are inadequate. Furthermore, the existing data for the real and imaginary parts of the refractive indices of dry sea salt aerosol are found not to display the Kramers-Kronig relationship. This implies that the original data used for the volume mixing calculations is also inaccurate.

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Laboratory measurements of the optical properties of sea salt aerosol

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-8-71-2008 ◽

2008 ◽

Vol 8 (1) ◽

pp. 71-94 ◽

Cited By ~ 2

Author(s):

R. Irshad ◽

R. G. Grainger ◽

D. M. Peters ◽

R. A. McPheat ◽

K. M. Smith ◽

...

Keyword(s):

Refractive Index ◽

Optical Properties ◽

Sea Salt ◽

Aerosol Size Distribution ◽

Refractive Indices ◽

Band Model ◽

Laboratory Measurements ◽

Sea Salt Aerosol ◽

Sea Salt Aerosols ◽

Ftir Spectrometer

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Densities, Viscosities and Refractive Indices of Ternary System Cyclohexane + Cyclohexanol + Cyclohexanone at 293.15, 298.15 and 303.15 K

Revista de Chimie ◽

10.37358/rc.19.4.7092 ◽

2019 ◽

Vol 70 (4) ◽

pp. 1204-1209

Author(s):

Maria Magdalena Budeanu ◽

Vasile Dumitrescu

Keyword(s):

Refractive Index ◽

Ternary System ◽

Linear Equation ◽

Viscous Flow ◽

Atmospheric Pressure ◽

Composition Range ◽

Refractive Indices ◽

Mixing Rules ◽

Experimental Values

Densities (r), viscosities (h) and refractive indices (nD) of the ternary system cyclohexane + cyclohexanol + cyclohexanone were measured at 293.15, 298.15 and 298.15 K and atmospheric pressure, over the whole composition range. The experimental values of densities and viscosities were correlated with temperature using a linear equation and Guzman equation respectively. Viscosity results were fitted with Grunberg-Nissan equation and Heric-Brewer equation. Different refractive index mixing rules (Arago-Biot, Dale-Glastone, Newton and Lorentz-Lorenz) were studied for this ternary system. The functions of activation of viscous flow were also calculated and their variations with compositions have been discussed.

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Viscosities and refractive indices of binary systems acetone+1-propanol, acetone+1,2-propanediol and acetone+1,3-propanediol

Chemical Industry and Chemical Engineering Quarterly ◽

10.2298/ciceq130305026z ◽

2014 ◽

Vol 20 (3) ◽

pp. 441-455 ◽

Cited By ~ 5

Author(s):

Emila Zivkovic ◽

Mirjana Kijevcanin ◽

Ivona Radovic ◽

Slobodan Serbanovic

Keyword(s):

Experimental Data ◽

Refractive Index ◽

Binary Mixtures ◽

Atmospheric Pressure ◽

Binary Systems ◽

Refractive Indices ◽

Mixing Rules ◽

Viscosity Deviations ◽

Kister Equation

Viscosities and refractive indices of three binary systems, acetone+1-propanol, acetone+1,2-propanediol and acetone+1,3-propanediol, were measured at eight temperatures (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, 323.15)K and at atmospheric pressure. From these data viscosity deviations and deviations in refractive index were calculated and fitted to the Redlich-Kister equation. The viscosity modelling was done by two types of models: predictive UNIFAC-VISCO and ASOG VISCO and correlative Teja-Rice and McAlister equations. The refractive indices of binary mixtures were predicted by various mixing rules and compared with experimental data.

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A kinetic model for ozone uptake by solutions and aqueous particles containing I− and Br−, including seawater and sea-salt aerosol

Physical Chemistry Chemical Physics ◽

10.1039/c9cp03430g ◽

2019 ◽

Vol 21 (36) ◽

pp. 19835-19856 ◽

Cited By ~ 9

Author(s):

Carolina Moreno ◽

María Teresa Baeza-Romero

Keyword(s):

Kinetic Model ◽

Surface Reactions ◽

Sea Salt ◽

Ozone Uptake ◽

Sea Salt Aerosol ◽

Sea Salt Aerosols ◽

Gaseous Ozone ◽

Heterogeneous Interactions ◽

Halogen Species

The heterogeneous interactions of gaseous ozone (O3) with seawater and with sea-salt aerosols are known to generate volatile halogen species, which, in turn, lead to further destruction of O3. Cl− acts as a catalyst in the surface reactions X− + O3.

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A New Instrument for Determining the Coarse-Mode Sea Salt Aerosol Size Distribution

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-20-0197.1 ◽

2021 ◽

Author(s):

Chung Taing ◽

Katherine L. Ackerman ◽

Alison D. Nugent ◽

Jorgen B. Jensen

Keyword(s):

Size Distribution ◽

Atmospheric Chemistry ◽

Optical Microscope ◽

Sea Salt ◽

Aerosol Size Distribution ◽

Sample Collection ◽

Sea Salt Aerosol ◽

Coarse Mode ◽

New Instrument ◽

Giant Nucleus

AbstractSea salt aerosol(s) (SSA) play a significant role in the atmosphere through aerosol direct and indirect effects, and in atmospheric chemistry as a source of tropospheric bromine. In-situ measurements of coarse-mode SSA particles are limited because of their low concentration and relatively large sizes (dry radius, rd > 0.5 μm). With this in mind, a new, low-cost, easily usable method for sampling coarse-mode SSA particles in the marine boundary layer was developed. A SSA particle sampler that uses an impaction method was designed and built using 3D printing and Arduino microcontrollers and sensors. It exposes polycarbonate slides to ambient airflow remotely on a kite-based platform to capture coarse-mode SSA particles. Because it is a smaller version of the Giant Nucleus Impactor (GNI), designed for use on aircraft, it is named the miniature-Giant Nucleus Impactor, or “mini-GNI”. After sample collection, the same optical microscope methodology utilized by the GNI was used to analyze the wetted salt particles that impacted onto the slides. In this proof-of-concept study, multiple mini-GNIs were attached serially to a kite string, allowing for sampling at multiple altitudes simultaneously. The robustness of the results from this new instrument and methodology for sampling at ambient RH (~ 75 %) the SSA particle size distribution with rd > 3.3 μ m are compared with a similar study. We find that the SSA particle number concentration decreases weakly with altitude and shows no correlation to instantaneous U10 wind speed along the windward coastline of O‘ ahu in the Hawaiian Islands.

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Modeling sea-salt aerosol in a coupled climate and sectional microphysical model: mass, optical depth and number concentration

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-24499-2010 ◽

2010 ◽

Vol 10 (10) ◽

pp. 24499-24561 ◽

Cited By ~ 4

Author(s):

T. Fan ◽

O. B. Toon

Keyword(s):

Wind Speed ◽

Size Distribution ◽

Optical Depth ◽

Source Function ◽

Removal Rate ◽

Global Climate Model ◽

Number Concentration ◽

Sea Salt ◽

Aerosol Size Distribution ◽

Sea Salt Aerosol

Abstract. Sea-salt aerosol mass, optical depth, and number concentration over the global oceans have significant implications for aerosol direct and indirect climate effects. We modeled sea-salt aerosol in a coupled climate and sectional microphysical model, CAM/CARMA, with aerosol dynamics including sea salt emission, gravitational sedimentation, dry deposition, wet scavenging, and particle swelling. We aimed at finding an integrated sea salt source function parameterization in the global climate model to simultaneously represent mass, optical depth, and number concentration. Each of these quantities is sensitive to a different part of the aerosol size distribution, which requires a size resolved microphysical model to treat properly. The CMS source function introduced in the research, based upon several earlier source functions, reproduced measurements of mass, optical depth and number concentration as well as the size distribution better than other source function choices we tried. However, as we note, it is also important to properly set the removal rate of the particles. The source function and removal rate are coupled in producing observed abundances. We find that sea-salt mass and optical depth peak in the winter, when winds are highest. However, surprisingly, particle numbers and CCN concentrations peak in summer when rainfall is lowest. The quadratic dependence of sea salt optical depth on wind speed, observed by some, is well represented in the model. We also found good agreement with the wind speed dependency of the number concentration at the measurement location and the regional scale. The work is the basis for further investigation of the effects of sea-salt aerosol on climate and atmospheric chemistry.

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Complex refractive indices in the ultraviolet and visible spectral region for highly absorbing non-spherical biomass burning aerosol

10.5194/acp-2020-1200 ◽

2020 ◽

Author(s):

Caroline C. Womack ◽

Katherine M. Manfred ◽

Nicholas L. Wagner ◽

Gabriela Adler ◽

Alessandro Franchin ◽

...

Keyword(s):

Refractive Index ◽

Optical Properties ◽

Black Carbon ◽

Biomass Burning ◽

Spectral Region ◽

Mie Theory ◽

Visible Spectral Region ◽

Aerosol Size Distribution ◽

Refractive Indices ◽

Biomass Burning Aerosol

Abstract. Biomass burning aerosol is a major source of PM2.5, and significantly affects Earth's radiative budget. The magnitude of its radiative effect is poorly quantified due to uncertainty in the optical properties of aerosol formed from biomass burning. Using a broadband cavity enhanced spectrometer with a recently increased spectral range (360–720 nm) coupled to a size-selecting aerosol inlet, we retrieve complex refractive indices of aerosol throughout the near-ultraviolet and visible spectral region. We demonstrate refractive index retrievals for two standard aerosol samples: polystyrene latex spheres and ammonium sulfate. We then retrieve refractive indices for biomass burning aerosol from 13 controlled fires during the 2016 Missoula Fire Science Laboratory Study. We demonstrate that the technique is highly sensitive to the accuracy of the aerosol size distribution method, and find that while we can constrain the optical properties of brown carbon aerosol for many fires, fresh smoke dominated by fractal-like black carbon aerosol presents unique challenges and is not well-represented by Mie theory. For the 13 fires, we show that the accuracy of Mie theory retrievals decreases as the fraction of black carbon mass increases. At 475 nm, the average refractive index is (1.635 ± 0.056) + (0.06 ± 0.12)i.

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Modeling sea-salt aerosol in a coupled climate and sectional microphysical model: mass, optical depth and number concentration

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-4587-2011 ◽

2011 ◽

Vol 11 (9) ◽

pp. 4587-4610 ◽

Cited By ~ 27

Author(s):

T. Fan ◽

O. B. Toon

Keyword(s):

Wind Speed ◽

Size Distribution ◽

Optical Depth ◽

Source Function ◽

Removal Rate ◽

Global Climate Model ◽

Number Concentration ◽

Sea Salt ◽

Aerosol Size Distribution ◽

Sea Salt Aerosol

Abstract. Sea-salt aerosol mass, optical depth, and number concentration over the global oceans have significant implications for aerosol direct and indirect climate effects. We model sea-salt aerosol in a coupled climate and sectional microphysical model, CAM/CARMA, with aerosol dynamics including sea-salt emission, gravitational sedimentation, dry deposition, wet scavenging, and hygroscopic growth. We aim to find an integrated sea-salt source function parameterization in the global climate model to simultaneously represent mass, optical depth, and number concentration. Each of these quantities is sensitive to a different part of the aerosol size distribution, which requires a size resolved microphysical model to treat properly. The CMS source function introduced in this research, based upon several earlier source functions, reproduces measurements of mass, optical depth and number concentration as well as the size distribution better than other source function choices we tried. However, as we note, it is also important to properly set the removal rate of the particles. The source function and removal rate are coupled in producing observed abundances. We find that sea salt mass and optical depth peak in the winter, when winds are highest. However, surprisingly, particle numbers and CCN concentrations peak in summer when rainfall is lowest. The quadratic dependence of sea-salt optical depth on wind speed, observed by some, is well represented in the model. We also find good agreement with the wind speed dependency of the number concentration at the measurement location and the regional scale. The work is the basis for further investigation of the effects of sea-salt aerosol on climate and atmospheric chemistry.

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Global simulations of nitrate and ammonium aerosols and their radiative effects

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-10115-2012 ◽

2012 ◽

Vol 12 (4) ◽

pp. 10115-10179 ◽

Cited By ~ 5

Author(s):

L. Xu ◽

J. E. Penner

Keyword(s):

Nitric Acid ◽

Dynamic Method ◽

Transport Model ◽

Sea Salt ◽

Chemistry Transport Model ◽

Salt Particle ◽

Acid Gas ◽

Sea Salt Aerosols ◽

Almost All ◽

Aerosol Activation

Abstract. We examine the formation of nitrate and ammonium on five types of externally mixed pre-existing aerosols using the hybrid dynamic method in a global chemistry transport model. The model developed here predicts a similar spatial pattern of total aerosol nitrate and ammonium to that of several pioneering studies, but separates the effects of nitrate and ammonium on pure sulfate, biomass burning, fossil fuel, dust and sea salt aerosols. Nitrate and ammonium boost the scattering efficiency of sulfate and organic matter but lower the extinction of sea salt particles since the hygroscopicity of a mixed nitrate-ammonium-sea salt particle is less than that of pure sea salt. The direct anthropogenic forcing of particulate nitrate and ammonium at the top of atmosphere (TOA) is estimated to be −0.12 W m−2. Nitrate, ammonium and nitric acid gas also affect aerosol activation and the reflectivity of clouds. The first aerosol indirect forcing by anthropogenic nitrate (gas plus aerosol) and ammonium is estimated to be −0.09 W m−2 at TOA, almost all of which is due to nitric acid gas (−0.08 W m−2).

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Study of Intermolecular Interactions of Binary Mixture of sec- and tert-Amines with Alkanols (C1-C3): Refractive Indices

Asian Journal of Chemistry ◽

10.14233/ajchem.2020.22719 ◽

2020 ◽

Vol 32 (10) ◽

pp. 2443-2449

Author(s):

Payal Bhagat ◽

Sanjeev Maken

Keyword(s):

Refractive Index ◽

Binary Mixture ◽

Chain Length ◽

Binary Mixtures ◽

Intermolecular Interactions ◽

Steric Hindrance ◽

Refractive Indices ◽

Mixing Rules ◽

Isopropyl Group

In this work, the refractive indices (nD) of binary mixture of diisopropylamine (DIPA) and tributylamine (TBA) (as sec- and tert-amines) with alkanol (methanol, ethanol, 1-propanol, 2-propanol) were measured from 298.15 K to 318.15 K. The sec- and tert-amines were selected to study the effect of branching at N-atom of amine on intermolecular interactions with alkanols having different chain length. It was found that the TBA interacts strongly with alkanol in comparison to DIPA due to steric hindrance offered by isopropyl group at N-atom. Various mixing rules were applied to evaluate the refractive index compared well with the experimental refractive indices data for the present binary mixtures. The experimental refractive indices was also fitted to Redlich-Kister polynomial.

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