Droplet Growth Kinetics of CCN From Biomass Burning and Secondary Organic Aerosol
American Geophysical Union Fall Meeting, San Francisco, CA
Organic aerosol can directly impact the ability of Cloud Condensation Nuclei (CCN) to turn into cloud droplets and potentially affect cloud formation and the hydrological cycle [Kanakidou, et al., 2005]]. The CCN activity and growth of both ambient and laboratory aerosol has been studied [Kanakidou, et al., 2005] yet the effect of organics on droplet growth kinetics has not been a strong focus in these investigations. Nevertheless, variable growth kinetics can have a substantial impact on droplet number and droplet spectral width; as a consequence may strongly impact cloud droplet formation [e.g., Lance, et al., 2004] with important implications for the aerosol indirect effects. In our study we investigate the growth kinetics of CCN derived from biomass burning, Secondary Organic Aerosol and Humic-like Substances. These experiments are then compared to the growth kinetics of pure ammonium sulfate CCN. A numerical model that simulates the supersaturation profiles within the instrument will be used to parameterize the droplet growth kinetics in terms of an effective water vapor accommodation coefficient. Understanding the effect of organic species on cloud droplet growth kinetics is imperative for reducing uncertainties in aerosol-cloud interaction studies. References: Kanakidou, M., et al. (2005), Organic aerosol and global climate modeling: a review, Atmospheric Chemistry And Physics, 5, 1053-1123. Lance, S., et al. (2004), Chemical and dynamical effects on cloud droplet number: Implications for estimates of the aerosol indirect effect, Journal Of Geophysical Research-Atmospheres, 109
Asa-Awuku, A.; Nenes, Athanasios; Sullivan, A.; Hennigan, C.; Weber, R.; Gao, Song; Sorooshian, Armin; Flagan, Richard C.; and Seinfeld, John H., "Droplet Growth Kinetics of CCN From Biomass Burning and Secondary Organic Aerosol" (2006). Chemistry and Physics Faculty Proceedings, Presentations, Speeches, Lectures. 54.