Precipitation effects of giant cloud condensation nuclei artificially introduced into stratocumulus clouds

TitlePrecipitation effects of giant cloud condensation nuclei artificially introduced into stratocumulus clouds
Publication TypeJournal Article
Year of Publication2015
AuthorsJung E, Albrecht BA, Jonsson H.H, Chen YC, Seinfeld JH, Sorooshian A, Metcalf AR, Song S, Fang M., Russell LM
JournalAtmospheric Chemistry and Physics
Volume15
Pagination5645-5658
Date Published2015/07
Type of ArticleArticle
ISBN Number1680-7316
Accession NumberWOS:000355289200020
Keywordsbalance; convective clouds; hygroscopic flares; marine stratocumulus; model; radar; simulation; warm rain
Abstract

To study the effect of giant cloud condensation nuclei (GCCN) on precipitation processes in stratocumulus clouds, 1-10 mu m diameter salt particles (salt powder) were released from an aircraft while flying near the cloud top on 3 August 2011 off the central coast of California. The seeded area was subsequently sampled from the aircraft that was equipped with aerosol, cloud, and precipitation probes and an upward-facing cloud radar. During post-seeding sampling, made 30-60 min after seeding, the mean cloud droplet size increased, the droplet number concentration decreased, and large drop (e.g., diameter larger than 10 mu m) concentration increased. Average drizzle rates increased from about 0.05 to 0.20 mm h(-1), and the liquid water path decreased from about 52 to 43 g m(-2). Strong radar returns associated with drizzle were observed on the post-seeding cloud-base level-leg flights and were accompanied by a substantial depletion of the cloud liquid water content. The changes were large enough to suggest that the salt particles with concentrations estimated to be 10(-2) to 10(-4) cm(-3) resulted in a four-fold increase in the cloud-base rainfall rate and depletion of the cloud water due to rainout. In contrast, a case is shown where the cloud was already precipitating (on 10 August) and the effect of adding GCCN to the cloud was insignificant.

DOI10.5194/acp-15-5645-2015
Short TitleAtmos. Chem. Phys.
Student Publication: 
No