Snowpack measurements suggest role for multi-year sea ice regions in Arctic atmospheric bromine and chlorine chemistry
| Autor: | Ignatius Rigor, Nathaniel W. May, James H. Morison, Michael Steele, Evan A. Schwartz, Kerri A. Pratt, Wendy Ermold, Mark Hartwig, Son V. Nghiem, Peter K. Peterson |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Atmospheric Science
Environmental Engineering food.ingredient 010504 meteorology & atmospheric sciences Sea ice 010501 environmental sciences Oceanography Atmospheric sciences 01 natural sciences Article Arctic food Snow lcsh:Environmental sciences 0105 earth and related environmental sciences lcsh:GE1-350 geography geography.geographical_feature_category Bromine Chlorine Halogen Ecology Sea salt Geology Snowpack Geotechnical Engineering and Engineering Geology Ozone depletion Trace gas 13. Climate action Atmospheric chemistry human activities |
| Zdroj: | Elem Sci Anth; Vol 7 (2019); 14 Elementa: Science of the Anthropocene, Vol 7, Iss 1 (2019) |
| ISSN: | 2325-1026 |
| Popis: | As sources of reactive halogens, snowpacks in sea ice regions control the oxidative capacity of the Arctic atmosphere. However, measurements of snowpack halide concentrations remain sparse, particularly in the high Arctic, limiting our understanding of and ability to parameterize snowpack participation in tropospheric halogen chemistry. To address this gap, we measured concentrations of chloride, bromide, and sodium in snow samples collected during polar spring above remote multi-year sea ice (MYI) and first-year sea ice(FYI) north of Greenland and Alask, as well as in the central Arctic, and compared these measurements to a larger dataset collected in the Alaskan coastal Arctic by Krnavek et al. (2012). Regardless of sea ice region, these surface snow samples generally featured lower salinities, compared to coastal snow. Surface snow in FYI regions was typically enriched in bromide and chloride compared to seawater, indicating snowpack deposition of bromine and chlorine-containing trace gases and an ability of the snowpack to participate further in bromine and chlorine activation processes. In contrast, surface snow in MYI regions was more often depleted in bromide, indicating it served as a source of bromine-containing trace gases to the atmosphere prior to sampling. Measurements at various snow depths indicate that the deposition of sea salt aerosols and halogen-containing trace gases to the snowpack surface played a larger role in determining surface snow halide concentrations compared to upward brine migration from sea ice. Calculated enrichment factors for bromide and chloride, relative to sodium, in the MYI snow samples suggests that MYI regions, in addition to FYI regions, have the potential to play an active role in Arctic boundary layer bromine and chlorine chemistry. The ability of MYI regions to participate in springtime atmospheric halogen chemistry should be considered in regional modeling of halogen activation and interpretation of satellite-based tropospheric bromine monoxide column measurements. |
| Databáze: | OpenAIRE |
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