H.: Photochemical production of molecular bromine in Arctic surface snowpacks, Nature Geosci

• Main Authors: Kerri A. Pratt, Kyle D. Custard, Paul B. Shepson, Thomas A. Douglas, Denis Pöhler, Stephan General, Johannes Zielcke, William R. Simpson, Ulrich Platt, David J. Tanner, L. Gregory Huey, Mark Carlsen, Brian H. Stirm
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Sea ice; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.640.8318; http://www.purdue.edu/discoverypark/climate/assets/pdfs/Photochemical production of molecular bromine in Arctic surface snowpacks.pdf

Following the springtime polar sunrise, ozone concentrations in the lower troposphere episodically decline to near-zero levels1. These ozone depletion events are initiated by an increase in reactive bromine levels in the atmosphere2–5. Under these conditions, the oxidative capacity of the Arctic troposphere is altered, leading to the removal of numerous transported trace gas pollutants, including mercury6. However, the sources and mechanisms leading to increased atmospheric reactive bromine levels have remained uncertain, limiting simulations of Arctic atmospheric chemistry with the rapidly transforming sea-ice landscape7,8. Here, we examine the potential for molecular bromine production in various samples of saline snow and sea ice, in the presence and absence of sunlight and ozone, in an outdoor snow chamber in Alaska. Molecular bromine was detected only on exposure of surface snow