title: Laboratory Studies of the Cloud Droplet Activation Properties and Corresponding Chemistry of Saline Playa Dust.
abstract: Playas emit large quantities of dust that can facilitate the activation of cloud droplets. Despite the potential importance of playa dusts for cloud formation, most climate models assume that all dust is nonhygroscopic; however, measurements are needed to clarify the role of dusts in aerosol-cloud interactions. Here, we report measurements of CCN activation from playa dusts and parameterize these results in terms of both κ-Köhler theory and adsorption activation theory for inclusion in atmospheric models. κ ranged from 0.002 ± 0.001 to 0.818 ± 0.094, whereas Frankel-Halsey-Hill (FHH) adsorption parameters of AFHH= 2.20 ± 0.60 and BFHH= 1.24 ± 0.14 described the water uptake properties of the dusts. Measurements made using aerosol time-of-flight mass spectrometry (ATOFMS) revealed the presence of halite, sodium sulfates, and sodium carbonates that were strongly correlated with κ underscoring the role that mineralogy, including salts, plays in water uptake by dust. Predictions of κ made using bulk chemical techniques generally showed good agreement with measured values. However, several samples were poorly predicted suggesting that chemical heterogeneities as a function of size or chemically distinct particle surfaces can determine the hygroscopicity of playa dusts. Our results further demonstrate the importance of dust in aerosol-cloud interactions.
authors.affiliation: Scripps Institution of Oceanography, University of California , San Diego, La Jolla, California 92093, United States.|Department of Atmospheric Sciences, Rosenstiel School of Marine & Atmospheric Science, University of Miami , Miami, Florida 33149, United States.
authors.forename: Cassandra J
authors.identifier: 0000-0003-1383-8585
authors.initials: CJ
authors.lastname: Gaston
authors.affiliation: Department of Chemistry and Biochemistry, University of California , San Diego, La Jolla, California 92093, United States.|Department of Chemistry, University of Michigan , Ann Arbor Michigan 48109, United States.
authors.forename: Kerri A
authors.identifier: 0000-0003-4707-2290
authors.initials: KA
authors.lastname: Pratt
authors.affiliation: Department of Chemistry and Biochemistry, University of California , San Diego, La Jolla, California 92093, United States.
authors.forename: Kaitlyn J
authors.initials: KJ
authors.lastname: Suski
authors.affiliation: Department of Chemistry, University of Michigan , Ann Arbor Michigan 48109, United States.
authors.forename: Nathaniel W
authors.initials: NW
authors.lastname: May
authors.affiliation: Environmental Science and Engineering Program, University of Texas at El Paso , El Paso, Texas 79968, United States.|Department of Geological Sciences, University of Texas at El Paso , El Paso, Texas 79968, United States.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Gill
authors.affiliation: Scripps Institution of Oceanography, University of California , San Diego, La Jolla, California 92093, United States.|Department of Chemistry and Biochemistry, University of California , San Diego, La Jolla, California 92093, United States.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Prather
mesh_terms: D000336:Aerosols; D002980:Climate; D004391:Dust; D012492:Salts; D017155:Wettability
chemical_list: D000336:Aerosols; D004391:Dust; D012492:Salts