CCN Properties of Organic Aerosol Collected Below and within Marine Stratocumulus Clouds near Monterey, California

Atmosphere

Akua Asa-Awuku¹  Armin Sorooshian⁴  Richard C. Flagan²  John H. Seinfeld³  Athanasios Nenes³ 

[1] Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA 92521, USA;Department of Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA; E-Mail:;Schools of Chemical and Biomolecular Engineering and Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA; E-Mail:;Departments of Chemical and Environmental Engineering, and Atmospheric Sciences University of Arizona, Tucson, AZ 85721, USA; E-Mail:

关键词: marine aerosol;    organics;    stratocumulus clouds;    cloud condensation nuclei;   

DOI  :  10.3390/atmos6111590

来源: mdpi

【 摘 要 】

The composition of aerosol from cloud droplets differs from that below cloud. Its implications for the Cloud Condensation Nuclei (CCN) activity are the focus of this study. Water-soluble organic matter from below cloud, and cloud droplet residuals off the coast of Monterey, California were collected; offline chemical composition, CCN activity and surface tension measurements coupled with Köhler Theory Analysis are used to infer the molar volume and surfactant characteristics of organics in both samples. Based on the surface tension depression of the samples, it is unlikely that the aerosol contains strong surfactants. The activation kinetics for all samples examined are consistent with rapid (NH₄)₂SO₄ calibration aerosol. This is consistent with our current understanding of droplet kinetics for ambient CCN. However, the carbonaceous material in cloud drop residuals is far more hygroscopic than in sub-cloud aerosol, suggestive of the impact of cloud chemistry on the hygroscopic properties of organic matter.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.