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| Titel |
A meta-analysis of particle water uptake reconciliation studies |
| VerfasserIn |
J. D. Whitehead, M. Irwin, J. D. Allan, N. Good, G. McFiggans |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 21 ; Nr. 14, no. 21 (2014-11-11), S.11833-11841 |
| Datensatznummer |
250119150
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| Publikation (Nr.) |
 copernicus.org/acp-14-11833-2014.pdf |
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| Zusammenfassung |
| Water uptake by aerosol particles controls their ability to form cloud
droplets, and reconciliation between different techniques for examining cloud condensation nuclei (CCN)
properties is important to our understanding of these processes and our
ability to measure and predict them. Reconciliation between measurements of
sub-saturated and supersaturated aerosol particle water uptake was attempted
at a wide range of locations between 2007 and 2013. The agreement in derived
number of CCN (NCCN or particle hygroscopicity
was mixed across the projects, with some data sets showing poor agreement
across all supersaturations and others agreeing within errors for at least
some of the supersaturation range. The degree of reconciliation did not seem
to depend on the environment in which the measurements were taken. The
discrepancies can only be attributable to differences in the chemical
behaviour of aerosols and gases in each instrument, leading to under- or
overestimated growth factors and/or CCN counts, though poorer reconciliation
at lower supersaturations can be attributed to uncertainties in the size
distribution at the threshold diameter found at these supersaturations. From
a single instrument, the variability in NCCN calculated using particle
hygroscopicity or size distribution averaged across a project demonstrates a
greater sensitivity to variation in the size distribution than chemical
composition in most of the experiments. However, the discrepancies between
instruments indicate a strong requirement for reliable quantification of CCN
in line with an improved understanding of the physical processes involved in
their measurement. Without understanding the reason for discrepancies in the
measurements, it is questionable whether quantification of CCN behaviour is
meaningful. |
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