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| Titel |
Wind tunnel experiments on the retention of trace gases during riming: nitric acid, hydrochloric acid, and hydrogen peroxide |
| VerfasserIn |
N. Blohn, K. Diehl, S. K. Mitra, S. Borrmann |
| 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 ; 11, no. 22 ; Nr. 11, no. 22 (2011-11-21), S.11569-11579 |
| Datensatznummer |
250010206
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| Publikation (Nr.) |
 copernicus.org/acp-11-11569-2011.pdf |
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| Zusammenfassung |
| Laboratory experiments were carried out in a vertical wind tunnel to study
the retention of different atmospheric trace gases during riming. In the
experiments, the rimed ice particles floated in a laminar air stream
carrying a cloud of supercooled droplets with radii between 10 and
20 μm. Ice particles, dendritic ice crystals, and snow flakes with diameters
between 6 mm and 1.5 cm were allowed to rime at temperatures between −5 and
−12 °C where riming mainly proceeds in the atmosphere and with cloud
liquid water contents between 1 and 1.5 g m−3 which are values
typically found in atmospheric mixed-phase clouds. Three trace species were
investigated, nitric and hydrochloric acid, and hydrogen peroxide. They were
present in the supercooled liquid droplets in concentrations from 1 to 120 ppmv,
i.e. similar to the concentrations measured in cloud drops. The
chemical analyses of the rimed ice particles allow one to determine the
trace species concentration in the ice phase. Together with the known liquid
phase concentration the retention coefficients were calculated in terms of
the amount of the species which remained in the ice phase after freezing. It
was found that the highly soluble trace gases, nitric and hydrochloric acid,
were retained nearly completely (98.6±8% and 99.7±9%,
respectively) while for hydrogen peroxide a retention of 64.3±11%
was determined. No influence of the riming temperature on the retention was
found which can be explained by the fact that in the observed range of
temperature and liquid water content, riming proceeded in the dry growth
regime. |
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