Observations of Bromine Monoxide Transport In the Arctic Sustained on Aerosol Particles
Peter K. Peterson1, Denis Pöhler2, Holger Sihler2,3, Johannes Zielcke2, Stephan General2, Udo Frieß2, Ulrich Platt2,3, William R. Simpson4, Son V. Nghiem5, Paul B. Shepson6, Brian H. Stirm7, Suresh Dhaniyala8, Thomas Wagner3, Dana R. Caulton9, Jose D. Fuentes10, and Kerri A. Pratt1,111Department of Chemistry, University of Michigan, Ann Arbor, MI, USA 2Institute of Environmental Physics, University of Heidelberg, Heidelberg, Germany 3Max Planck Institute for Chemistry, Mainz, Germany 4Department of Chemistry and Biochemistry and Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska, USA 5Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA 6Department of Chemistry, Department of Earth, Planetary, and Atmospheric Sciences, and Purdue Climate Change Research Center, Purdue University, West Lafayette, IN, USA 7School of Aviation and Transportation Technology, Purdue University, West Lafayette, IN, USA 8Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY, USA 9Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, USA 10Department of Meteorology, The Pennsylvania State University, University Park, PA, USA 11Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
Received: 21 Dec 2016 – Accepted for review: 20 Feb 2017 – Discussion started: 23 Feb 2017
Abstract. The return of sunlight in the polar spring leads to production of reactive halogen species from the surface snowpack, significantly altering the chemical composition of the Arctic near-surface atmosphere and the fate of long-range transported pollutants, including mercury. Recent work has shown the initial production of reactive bromine at the Arctic surface snowpack; however, we have limited knowledge of the vertical extent of this chemistry, as well as the lifetime and possible transport of reactive bromine aloft. Here, we present bromine monoxide (BrO) and aerosol particle measurements obtained during the March 2012 BRomine Ozone Mercury EXperiment (BROMEX) near Utqiagvik (Barrow), AK. The airborne differential optical absorption spectroscopy (DOAS) measurements provided an unprecedented level of spatial resolution, over two orders of magnitude greater than satellite observations and with vertical resolution unable to be achieved by satellite methods, for BrO in the Arctic. This novel method provided quantitative identification of a BrO plume, disconnected from the surface, moving at the speed of the air mass. This lofted reactive bromine plume was transported and maintained at elevated levels through heterogeneous reactions on co-located supermicron aerosol particles, independently of surface snowpack bromine chemistry. This chemical transport mechanism significantly increases the spatial extent of this reactive bromine chemistry, impacting atmospheric composition and pollutant fate across the region, beyond the area of initial snowpack halogen production. This process must be considered in the interpretation of satellite BrO observations and examined in the context of the rapidly changing Arctic sea ice and snowpack.
Peterson, P. K., Pöhler, D., Sihler, H., Zielcke, J., General, S., Frieß, U., Platt, U., Simpson, W. R., Nghiem, S. V., Shepson, P. B., Stirm, B. H., Dhaniyala, S., Wagner, T., Caulton, D. R., Fuentes, J. D., and Pratt, K. A.: Observations of Bromine Monoxide Transport In the Arctic Sustained on Aerosol Particles, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-1141, in review, 2017.