Photochemistry and nature of organic matter in Arctic and Antarctic snow

It has been shown that sunlit snowpacks are photochemically active, producing a number of species that can significantly impact the overlying atmosphere. Here we investigate the origin of the flux of low molecular weight carbonyl compounds (formaldehyde and acetaldehyde) from sunlit snow obtained from both Arctic (Alert, Canada, and Summit, Greenland) and Antarctic (South Pole) sources. In addition, efforts to characterize the potential snow-phase organic matter (SPOM) precursors were undertaken. Using chemically characterized SPOM, we find that formaldehyde and acetaldehyde are produced upon irradiation, and that production is enhanced with the addition of nitrate (a precursor to OH radicals). SPOM from both Alert and Summit is found to be derived from a variety of sources, including vascular plants. This indicates deposition of atmospheric particulate matter containing vascular tissue to high-altitude Arctic snow. These findings open a potential window for a rich record of variations in terrestrial vegetation-derived aerosol signals that could be preserved in ice cores.