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| Titel |
A review of air–ice chemical and physical interactions (AICI): liquids, quasi-liquids, and solids in snow |
| VerfasserIn |
T. Bartels-Rausch, H.-W. Jacobi, T. F. Kahan, J. L. Thomas, E. S. Thomson, J. P. D. Abbatt, M. Ammann, J. R. Blackford, H. Bluhm, C. Boxe, F. Domine, M. M. Frey, I. Gladich, M. I. Guzmán, D. Heger, Th. Huthwelker, P. Klán, W. F. Kuhs, M. H. Kuo, S. Maus, S. G. Moussa, V. F. McNeill, J. T. Newberg, J. B. C. Pettersson, M. Roeselová, J. R. Sodeau |
| 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. 3 ; Nr. 14, no. 3 (2014-02-12), S.1587-1633 |
| Datensatznummer |
250118371
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| Publikation (Nr.) |
 copernicus.org/acp-14-1587-2014.pdf |
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| Zusammenfassung |
Snow in the environment acts as a host to rich chemistry and provides
a matrix for physical exchange of contaminants within the ecosystem. The goal
of this review is to summarise the current state of knowledge of physical
processes and chemical reactivity in surface snow with relevance to polar
regions. It focuses on a description of impurities in distinct compartments
present in surface snow, such as snow crystals, grain boundaries, crystal
surfaces, and liquid parts. It emphasises the microscopic description of the
ice surface and its link with the environment. Distinct differences between
the disordered air–ice interface, often termed quasi-liquid layer, and
a liquid phase are highlighted. The reactivity in these different
compartments of surface snow is discussed using many experimental studies,
simulations, and selected snow models from the molecular to the macro-scale.
Although new experimental techniques have extended our knowledge of the
surface properties of ice and their impact on some single reactions and
processes, others occurring on, at or within snow grains remain unquantified.
The presence of liquid or liquid-like compartments either due to the
formation of brine or disorder at surfaces of snow crystals below the
freezing point may strongly modify reaction rates. Therefore, future
experiments should include a detailed characterisation of the surface
properties of the ice matrices. A further point that remains largely
unresolved is the distribution of impurities between the different domains of
the condensed phase inside the snowpack, i.e. in the bulk solid, in liquid at
the surface or trapped in confined pockets within or between grains, or at
the surface. While surface-sensitive laboratory techniques may in the future
help to resolve this point for equilibrium conditions, additional uncertainty
for the environmental snowpack may be caused by the highly dynamic nature of
the snowpack due to the fast metamorphism occurring under certain
environmental conditions.
Due to these gaps in knowledge the first snow chemistry models have attempted
to reproduce certain processes like the long-term incorporation of volatile
compounds in snow and firn or the release of reactive species from the
snowpack. Although so far none of the models offers a coupled approach of
physical and chemical processes or a detailed representation of the different
compartments, they have successfully been used to reproduce some field
experiments. A fully coupled snow chemistry and physics model remains to be
developed. |
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