The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

TitleThe role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles
Publication TypeJournal Article
Year of Publication2017
AuthorsWang X.F, Deane GB, Moore K.A, Ryder OS, Stokes MD, Beall C.M, Collins DB, Santander M.V, Burrows S.M, Sultana C.M, Prather KA
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Pagination6978-6983
Date Published2017/07
Type of ArticleArticle
ISBN Number0027-8424
Accession NumberWOS:000404576100049
Keywordsbreaking wave analog; bubble bursting; film drop; ice-nucleating particles; jet drop; mixing state; ocean; primary marine aerosol; sea spray aerosol; seawater; size
Abstract

The oceans represent a significant global source of atmospheric aerosols. Sea spray aerosol (SSA) particles comprise sea salts and organic species in varying proportions. In addition to size, the overall composition of SSA particles determines how effectively they can form cloud droplets and ice crystals. Thus, understanding the factors controlling SSA composition is critical to predicting aerosol impacts on clouds and climate. It is often assumed that submicrometer SSAs are mainly formed by film drops produced from bursting bubble-cap films, which become enriched with hydrophobic organic species contained within the sea surface microlayer. In contrast, jet drops formed from the base of bursting bubbles are postulated to mainly produce larger supermicrometer particles from bulk seawater, which comprises largely salts and water-soluble organic species. However, here we demonstrate that jet drops produce up to 43% of total submicrometer SSA number concentrations, and that the fraction of SSA produced by jet drops can be modulated by marine biological activity. We show that the chemical composition, organic volume fraction, and ice nucleating ability of submicrometer particles from jet drops differ from those formed from film drops. Thus, the chemical composition of a substantial fraction of submicrometer particles will not be controlled by the composition of the sea surface microlayer, a major assumption in previous studies. This finding has significant ramifications for understanding the factors controlling the mixing state of submicrometer SSA particles and must be taken into consideration when predicting SSA impacts on clouds and climate.

DOI10.1073/pnas.1702420114
Student Publication: 
No