Aerosol optical hygroscopicity measurements during the 2010 CARES campaign
Name
Atkinson-2015-Aerosol optical hygr.pdf
Size
2.3 MB
Format
Adobe PDF
Checksum (MD5)
8d57e458d7d4d967ac8e12e5b21d4554
Author(s)
Atkinson, D. B.
Radney, J. G.
Lum, J.
Kolesar, K. R.
Pekour, M. S.
Zhang, Q.
Setyan, A.
Zelenyuk, A.
Cappa, C. D.
Cziczo, Daniel James
Date Issued
April 2015
Journal
Atmospheric Chemistry and Physics
Publisher
Copernicus GmbH
Citation
Atkinson, D. B., J. G. Radney, J. Lum, K. R. Kolesar, D. J. Cziczo, M. S. Pekour, Q. Zhang, A. Setyan, A. Zelenyuk, and C. D. Cappa. “Aerosol Optical Hygroscopicity Measurements During the 2010 CARES Campaign.” Atmos. Chem. Phys. 15, no. 8 (2015): 4045–4061.
Version
Final published version
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.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.5194/acp-15-4045-2015
