Abstract
A field study was conducted at a mountain-top site in northwestern Colorado. Supercooled cloud water, collected as a function of droplet size, was analyzed for anions, cations and trace elements. Enrichment factors (EF) of SO 4 2− , K+, Na+ and Cl− relative to crustal and marine reference elements (Al and Na) were calculated to determine whether chemical fractionation of the aerosol occurs during cloud droplet formation. The largest EF's for all ions were found for droplets less than 10–15 µm diameter. Ratios of the small to large droplet mean EF's ranged from 1 to 2, for SO 4 2− relative to both Al and Na+, to 10 to 12 for Na+, Cl− and K+, relative to Al. EF's of K+ and Cl− in the bulk cloud water were in crustal and marine proportions, respectively. It was concluded that although bulk could chemistry may indicate a lack of enrichment of a species, this may not be true throughout the droplet size distribution. The higher enrichments in small droplets is likely a result of their formation on small aerosol particles whereas the large droplets form on the largest aerosol particles. This may suppress EF's in precipitation relative to the total aerosol.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
