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 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 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 Secondary aerosol formation promotes water uptake by organic-rich wildfire haze particles in Equatorial Asia

2017 ◽  
Author(s):  
Jing Chen ◽  
Sri Hapsari Budisulistiorini ◽  
Takuma Miyakawa ◽  
Yuichi Komazaki ◽  
Mikinori Kuwata
Keyword(s):  
Water Uptake ◽  
Mass Fraction ◽  
Water Soluble ◽  
Submicron Particles ◽  
Chemical Information ◽  
Hygroscopic Growth ◽  
Aerosol Formation ◽  
Secondary Formation ◽  
Soluble Organic Fraction ◽  
Haze Episode

Abstract. Diameter growth factors (GF) of 100 nm haze particles at 85 % relative humidity and chemical characteristics were simultaneously monitored at Singapore in October 2015 during a pervasive wildfire haze episode, which was caused by peatland burning in Indonesia. Non-refractory submicron particles (NR-PM1) were dominated by organics (approximating 77.1 % in total mass), whereas sulfate was the most abundant inorganic constituent (11.7 % on average). A statistical analysis of the organic mass spectra showed that most of organics (36.0 % of NR-PM1 mass) were highly oxygenated. Diurnal variations of GF, number fraction of highly hygroscopic mode particles, mass fraction of sulfate, and mass fraction of oxygenated organics (OOA) synchronized well, peaking during daytime. The mean hygroscopicity parameter (κ) of haze particles was 0.189 ± 0.087, and mean κ values of organics were 0.157 ± 0.108 (κorg, bulk organics) and 0.287 ± 0.193 (κOOA, OOA), demonstrating the important roles of both sulfate and highly oxygenated organics in hygroscopic growth of wildfire haze particles. κorg was also affected by the water-soluble organic fraction to some extent. These results show the importance of secondary formation processes in promoting water uptake properties of wildfire haze particles, including both inorganic and organic species. Further detailed size-resolved as well as molecular level chemical information of organics will be necessary for more profound exploration of water uptake by wildfire haze particles in Equatorial Asia.

Influence of water filtration on the determination of a wide range of dissolved contaminants at parts-per-trillion levels

2007 ◽  
Vol 583 (1) ◽  
pp. 202-209 ◽  
Author(s):  
Anna Gómez-Gutiérrez ◽  
Eric Jover ◽  
Josep M. Bayona ◽  
Joan Albaigés
Keyword(s):  
Water Filtration ◽  
Wide Range ◽  
Influence Of Water
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