 |
| Titel |
An overview of snow photochemistry: evidence, mechanisms and impacts |
| VerfasserIn |
A. M. Grannas, A. E. Jones, J. Dibb, M. Ammann, C. Anastasio, H. J. Beine, M. Bergin, J. Bottenheim, C. S. Boxe, G. Carver, G. Chen, J. H. Crawford, F. Domine, M. M. Frey, M. I. Guzmán, D. E. Heard, D. Helmig, M. R. Hoffmann, R. E. Honrath, L. G. Huey, M. Hutterli, H. W. Jacobi, P. Klán, B. Lefer, J. McConnell, J. Plane, R. Sander, J. Savarino, P. B. Shepson, W. R. Simpson, J. R. Sodeau, R. Glasow, R. Weller, E. W. Wolff, T. Zhu |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 7, no. 16 ; Nr. 7, no. 16 (2007-08-22), S.4329-4373 |
| Datensatznummer |
250005173
|
| Publikation (Nr.) |
 copernicus.org/acp-7-4329-2007.pdf |
|
|
|
|
|
| Zusammenfassung |
| It has been shown that sunlit snow and ice plays an important role in
processing atmospheric species. Photochemical production of a variety of
chemicals has recently been reported to occur in snow/ice and the release of
these photochemically generated species may significantly impact the
chemistry of the overlying atmosphere. Nitrogen oxide and oxidant precursor
fluxes have been measured in a number of snow covered environments, where in
some cases the emissions significantly impact the overlying boundary layer.
For example, photochemical ozone production (such as that occurring in
polluted mid-latitudes) of 3–4 ppbv/day has been observed at South Pole, due
to high OH and NO levels present in a relatively shallow boundary layer. Field
and laboratory experiments have determined that the origin of the observed
NOx flux is the photochemistry of nitrate within the snowpack, however some
details of the mechanism have not yet been elucidated. A variety of low
molecular weight organic compounds have been shown to be emitted from sunlit
snowpacks, the source of which has been proposed to be either direct or
indirect photo-oxidation of natural organic materials present in the snow.
Although myriad studies have observed active processing of species within
irradiated snowpacks, the fundamental chemistry occurring remains poorly
understood. Here we consider the nature of snow at a fundamental, physical
level; photochemical processes within snow and the caveats needed for
comparison to atmospheric photochemistry; our current understanding of
nitrogen, oxidant, halogen and organic photochemistry within snow; the
current limitations faced by the field and implications for the future. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|