In:
Science, American Association for the Advancement of Science (AAAS), Vol. 351, No. 6280 ( 2016-03-25), p. 1447-1450
Kurzfassung:
Accurate predictions of aerosol/cloud interactions require simple, physically accurate parameterizations of the cloud condensation nuclei (CCN) activity of aerosols. Current models assume that organic aerosol species contribute to CCN activity by lowering water activity. We measured droplet diameters at the point of CCN activation for particles composed of dicarboxylic acids or secondary organic aerosol and ammonium sulfate. Droplet activation diameters were 40 to 60% larger than predicted if the organic was assumed to be dissolved within the bulk droplet, suggesting that a new mechanism is needed to explain cloud droplet formation. A compressed film model explains how surface tension depression by interfacial organic molecules can alter the relationship between water vapor supersaturation and droplet size (i.e., the Köhler curve), leading to the larger diameters observed at activation.
Materialart:
Online-Ressource
ISSN:
0036-8075
,
1095-9203
DOI:
10.1126/science.aad4889
Sprache:
Englisch
Verlag:
American Association for the Advancement of Science (AAAS)
Publikationsdatum:
2016
ZDB Id:
128410-1
ZDB Id:
2066996-3
ZDB Id:
2060783-0
SSG:
11
