An overview of snow photochemistry: evidence, mechanisms and impacts

• Main Authors: Grannas, A. M., Jones, A. E., Dibb, J., Ammann, M., Anastasio, C., Beine, H. J., Bergin, M., Bottenheim, J., Boxe, C. S., Carver, G., Chen, G., Crawford, J. H., Dominé, F., Frey, M. M., Guzmán, M. I., Heard, D. E., Helmig, D., Hoffmann, M. R., Honrath, R. E., Huey, L. G., Hutterli, M., Jacobi, H. W., Klán, P., Lefer, B., Mcconnell, J., Plane, J., Sander, R., Savarino, J., Shepson, P. B., Simpson, W. R., Sodeau, J. R., von Glasow, R., Weller, R., Wolff, E. W., Zhu, T.
• Other Authors: Department of Chemistry, Villanova University USA, British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Institute for Study of Earth, Oceans and Space, University of New Hampshire (UNH), Laboratory for Radio- and Environmental Chemistry, Department of Land, Air {&} Water Resources, National Research Council of Italy, School of Earth and Atmospheric Sciences Atlanta, Georgia Institute of Technology Atlanta, Air Quality Research Branch, Environment and Climate Change Canada (ECCC), W. M. Keck Laboratories, California Institute of Technology (CALTECH), Centre for Atmospheric Science Cambridge, UK, University of Cambridge UK (CAM), NASA Langley Research Center Hampton (LaRC), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Engineering, University of California Merced (UC Merced), University of California (UC)-University of California (UC), School of Chemistry Leeds, University of Leeds, Institute of Arctic Alpine Research University of Colorado Boulder (INSTAAR), University of Colorado Boulder, Department of Civil and Environmental Engineering Michigan (CEE), Michigan Technological University (MTU), Department of Bentho-pelagic processes, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, Masaryk University Brno (MUNI), Department of Geosciences Houston, University of Houston, Department of Earth and Space Science and Engineering York University - Toronto (ESSE), York University Toronto, Atmospheric Chemistry Department MPIC, Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Department of Chemistry West Lafayette, Purdue University West Lafayette, Department of Chemistry and Geophysical Institute, University of Alaska Fairbanks (UAF), School of Environmental Sciences Norwich, University of East Anglia Norwich (UEA), Institute of Environmental Physics Heidelberg (IUP), Universität Heidelberg Heidelberg = Heidelberg University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; South pole
• Online Access: https://hal.science/hal-00328525; https://hal.science/hal-00328525/document; https://hal.science/hal-00328525/file/acp-7-4329-2007.pdf

International audience 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 NO x 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.