scholarly journals Aerosol optical hygroscopicity measurements during the 2010 CARES Campaign

2014 ◽  
Vol 14 (22) ◽  
pp. 31203-31247 ◽  
Author(s):  
D. B. Atkinson ◽  
J. G. Radney ◽  
J. Lum ◽  
K. R. Kolesar ◽  
D. J. Cziczo ◽  
...  
Keyword(s):  
Water Uptake ◽  
Organic Aerosol ◽  
Light Extinction ◽  
Hygroscopic Growth ◽  
Particle Size Distributions ◽  
Range Analysis ◽  
Size Dependent ◽  
Atmospheric Processing ◽  
Influence Of Water

Abstract. Measurements of the effect of water uptake on particulate light extinction or scattering made at two locations during the 2010 CARES study around Sacramento, CA are reported. The observed influence of water uptake, characterized through the dimensionless optical hygroscopicity parameter γ, is compared with calculations constrained by observed particle size distributions and size-dependent particle composition. A closure assessment has been carried out that allowed for determination of the average hygroscopic growth factors (GF) at 85% relative humidity and the dimensionless hygroscopicity parameter κ for oxygenated organic aerosol (OA) and for supermicron particles, yielding κ = 0.1–0.15 and 0.9–1.0, respectively. The derived range of oxygenated OA κ values are in line with previous observations. The relatively large values for supermicron particles is consistent with substantial contributions of sea salt-containing particles in this size range. Analysis of time-dependent variations in the supermicron particle hygroscopicity suggest that atmospheric processing, specifically chloride displacement by nitrate and the accumulation of secondary organics on supermicron particles, can lead to substantial depression of the observed GF.

scholarly journals Aerosol optical hygroscopicity measurements during the 2010 CARES campaign

2015 ◽  
Vol 15 (8) ◽  
pp. 4045-4061 ◽  
Author(s):  
D. B. Atkinson ◽  
J. G. Radney ◽  
J. Lum ◽  
K. R. Kolesar ◽  
D. J. Cziczo ◽  
...  
Keyword(s):  
Water Uptake ◽  
Light Extinction ◽  
Carbonaceous Aerosols ◽  
Hygroscopic Growth ◽  
Particle Size Distributions ◽  
Range Analysis ◽  
Size Dependent ◽  
Atmospheric Processing ◽  
Influence Of Water

Abstract. Measurements of the effect of water uptake on particulate light extinction or scattering made at two locations during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) study around Sacramento, CA are reported. The observed influence of water uptake, characterized through the dimensionless optical hygroscopicity parameter γ, is compared with calculations constrained by observed particle size distributions and size-dependent particle composition. A closure assessment has been carried out that allowed for determination of the average hygroscopic growth factors (GFs) at 85% relative humidity and the dimensionless hygroscopicity parameter κ for oxygenated organic aerosol (OA) and for supermicron particles (defined here as particles with aerodynamic diameters between 1 and 2.5 microns), yielding κ = 0.1–0.15 and 0.9–1.0, respectively. The derived range of oxygenated OA κ values are in line with previous observations. The relatively large values for supermicron particles is consistent with substantial contributions of sea-salt-containing particles in this size range. Analysis of time-dependent variations in the supermicron particle hygroscopicity suggest that atmospheric processing, specifically chloride displacement by nitrate and the accumulation of secondary organics on supermicron particles, can lead to substantial depression of the observed GF.

scholarly journals Size-dependent activation of aerosols into cloud droplets at a subarctic background site during the second Pallas Cloud Experiment (2nd PaCE): method development and data evaluation

2009 ◽  
Vol 9 (14) ◽  
pp. 4841-4854 ◽  
Author(s):  
T. Anttila ◽  
P. Vaattovaara ◽  
M. Komppula ◽  
A.-P. Hyvärinen ◽  
H. Lihavainen ◽  
...  
Keyword(s):  
Growth Factors ◽  
Water Uptake ◽  
Method Development ◽  
Water Soluble ◽  
Hygroscopic Growth ◽  
Mixing State ◽  
Cloud Droplets ◽  
Important Conclusion ◽  
Size Dependent ◽  
Background Site

Abstract. In situ measurements of aerosol water uptake and activation of aerosols into cloud droplets provide information on how aerosols influence the microphysical properties of clouds. Here we present a computational scheme that can be used in connection with such measurements to assess the influence of the particle hygroscopicity and mixing state (in terms of the water uptake) on the cloud nucleating ability of particles. Additionally, it provides an estimate for the peak supersaturation of water vapour reached during the formation of the observed cloud(s). The method was applied in interpreting results of a measurement campaign that focused on aerosol-cloud interactions taking place at a subarctic background site located in Northern Finland (second Pallas Cloud Experiment, 2nd PaCE). A set of case studies was conducted, and the observed activation behavior could be successfully explained by a maximum supersaturation that varied between 0.18 and 0.26% depending on the case. In these cases, the diameter corresponding to the activated fraction of 50% was in the range of 110–140 nm, and the particles were only moderately water soluble with hygroscopic growth factors varying between 1.1 and 1.4. The conducted analysis showed that the activated fractions and the total number of particles acting as CCN are expected to be highly sensitive to the particle hygroscopic growth properties. For example, the latter quantity varied over a factor between 1.8 and 3.1, depending on the case, when the mean hygroscopic growth factors were varied by 10%. Another important conclusion is that size-dependent activation profiles carries information on the mixing state of particles.

scholarly journals Size-dependent activation of aerosols into cloud droplets at a subarctic background site during the second Pallas Cloud Experiment (2nd PaCE): method development and data evaluation

2008 ◽  
Vol 8 (4) ◽  
pp. 14519-14556
Author(s):  
T. Anttila ◽  
P. Vaattovaara ◽  
M. Komppula ◽  
A.-P. Hyvärinen ◽  
H. Lihavainen ◽  
...  
Keyword(s):  
Growth Factors ◽  
Water Uptake ◽  
Method Development ◽  
Water Soluble ◽  
Hygroscopic Growth ◽  
Mixing State ◽  
Cloud Droplets ◽  
Important Conclusion ◽  
Size Dependent ◽  
Background Site

Abstract. In situ measurements of aerosol water uptake and activation of aerosols into cloud droplets provide information on how aerosols influence the microphysical properties of clouds. Here we present a computational scheme that can be used in connection with such measurements to assess the influence of the particle chemical composition and mixing state (in terms of the water uptake) on the cloud nucleating ability of particles. Additionally, it provides an estimate for the peak supersaturation of water vapour reached during the formation of the observed cloud(s). The method was applied in interpreting results of a measurement campaign that focused on aerosol-cloud interactions taking place at a subarctic background site located in northern Finland (second Pallas Cloud Experiment, 2nd PaCE). A set of case studies was conducted, and the observed activation behavior could be successfully explained by a maximum supersaturation that varied between 0.18 and 0.26% depending on the case. In these cases, the diameter corresponding to the activated fraction of 50% was in the range of 110–140 nm, and the particles were only moderately water soluble with hygroscopic growth factors varying between 1.1 and 1.4. The conducted analysis showed that the activated fractions and the total number of particles acting as CCN are expected to be highly sensitive to the particle hygroscopicity. For example, the latter quantity varied over a factor between 1.8 and 3.1, depending on the case, when the mean hygroscopic growth factors were varied by 10%. Another important conclusion is that size-dependent activation profiles carries information on the mixing state of particles.

scholarly journals Shining New Light on the Kinetics of Water Uptake by Organic Aerosol Particles

2021 ◽  
Author(s):  
Matus E. Diveky ◽  
Michael J. Gleichweit ◽  
Sandra Roy ◽  
Ruth Signorell
Keyword(s):  
Water Uptake ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Kinetics Of

Experimental determination of chemical diffusion within secondary organic aerosol particles

2013 ◽  
Vol 15 (8) ◽  
pp. 2983 ◽  
Author(s):  
Evan Abramson ◽  
Dan Imre ◽  
Josef Beránek ◽  
Jacqueline Wilson ◽  
Alla Zelenyuk
Keyword(s):  
Experimental Determination ◽  
Secondary Organic Aerosol ◽  
Aerosol Particles ◽  
Chemical Diffusion ◽  
Organic Aerosol

Determination of the viscosity of levitated droplets at atmospheric temperatures in an electrodynamic trap

2021 ◽  
Author(s):  
Stephanie Jones ◽  
Mohit Singh ◽  
Denis Duft ◽  
Alexei Kiselev ◽  
Thomas Leisner
Keyword(s):  
Amorphous Solid ◽  
Organic Aerosol ◽  
Photochemical Reactions ◽  
Temperature Range ◽  
Ability To Act ◽  
Levitated Droplets ◽  
Semi Solid ◽  
Future Work ◽  
The Impact

<p>The impact of atmospheric aerosol on the climate remains poorly understood. Organic aerosol makes up a significant fraction of total aerosol and is prevalent throughout the atmosphere. It can exist as a liquid, semi-solid or amorphous solid. The viscosity of organic aerosol will have an impact on transformations that organic aerosol will undergo during its lifetime such as evaporation and growth, heterogeneous and photochemical reactions as well as the ability to act as an ice nucleating particle.  Therefore, it is of key importance to be able to determine aerosol viscosity over a range of atmospherically relevant conditions in order to better understand the impact of organic aerosol on the climate.</p> <p>Here we report proof of concept viscosity measurements of water droplets levitated in an electrodynamic balance over a range of temperatures. Charged droplets are levitated in a temperature and relative humidity-controlled environment allowing properties over a temperature range of 300 to 220 K to be studied. As the droplets evaporate they reach a point where Coulomb instabilities are induced resulting in droplet oscillations. The relaxation of these oscillations can then be probed to determine the droplet viscosity. Future work will involve determination of the viscosity of different types of organic aerosol over a broad temperature range.</p>

Sign in / Sign up

Export Citation Format

Share Document