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| Titel |
Seasonal variability of Saharan desert dust and ice nucleating particles over Europe |
| VerfasserIn |
L. B. Hande, C. Engler, C. Hoose, I. Tegen |
| 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 ; 15, no. 8 ; Nr. 15, no. 8 (2015-04-30), S.4389-4397 |
| Datensatznummer |
250119671
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| Publikation (Nr.) |
 copernicus.org/acp-15-4389-2015.pdf |
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| Zusammenfassung |
| Dust aerosols are thought to be the main contributor to atmospheric ice
nucleation. While there are case studies supporting this, a climatological
sense of the importance of dust to atmospheric ice nucleating particle (INP)
concentrations and its seasonal variability over Europe is lacking. Here, we
use a mesoscale model to estimate Saharan dust concentrations over Europe in
2008. There are large differences in median dust concentrations between
seasons, with the highest concentrations and highest variability in the lower
to mid-troposphere. Laboratory-based ice nucleation parameterisations are
applied to these simulated dust number concentrations to calculate the
potential INP resulting from immersion freezing and deposition nucleation on
these dust particles. The potential INP concentrations increase exponentially
with height due to decreasing temperatures in the lower and mid-troposphere.
When the ice-activated fraction increases sufficiently, INP concentrations
follow the dust particle concentrations. The potential INP profiles exhibit
similarly large differences between seasons, with the highest concentrations
in spring (median potential immersion INP concentrations nearly 105
m−3, median potential deposition INP concentrations at 120%
relative humidity with respect to ice over 105 m−3), about an
order of magnitude larger than those in summer. Using these results, a
best-fit function is provided to estimate the potential INPs for use in
limited-area models, which is representative of the normal background INP
concentrations over Europe. A statistical evaluation of the results against
field and laboratory measurements indicates that the INP concentrations are
in close agreement with observations. |
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