Bromine measurements in ozone depleted air over the Arctic Ocean

Authors

J A. Neuman, University of Colorado Boulder
J Nowak, NOAA
L Gregory Huey, Georgia Institute of Technology - Main Campus
J B. Burkholder, NOAA
Jack E. Dibb, University of New HampshireFollow
J S. Holloway, University of Colorado Boulder
J Liao, Georgia Institute of Technology - Main Campus
Jeff Peischl, NOAA
J M. Roberts, NOAA
Thomas B. Ryerson, NOAA
Eric Scheuer, University of New Hampshire - Main CampusFollow
H Stark, University of Colorado Boulder
R E. Stickel, Georgia Institute of Technology - Main Campus
D Tanner, Georgia Institute of Technology - Main Campus
Andrew Weinheimer, National Center for Atmospheric Research

Abstract

In situ measurements of ozone, photochemically active bromine compounds, and other trace gases over the Arctic Ocean in April 2008 are used to examine the chemistry and geographical extent of ozone depletion in the arctic marine boundary layer (MBL). Data were obtained from the NOAA WP-3D aircraft during the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) study and the NASA DC-8 aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) study. Fast (1 s) and sensitive (detection limits at the low pptv level) measurements of BrCl and BrO were obtained from three different chemical ionization mass spectrometer (CIMS) instruments, and soluble bromide was measured with a mist chamber. The CIMS instruments also detected Br₂. Subsequent laboratory studies showed that HOBr rapidly converts to Br₂ on the Teflon instrument inlets. This detected Br₂ is identified as active bromine and represents a lower limit of the sum HOBr + Br₂. The measured active bromine is shown to likely be HOBr during daytime flights in the arctic. In the MBL over the Arctic Ocean, soluble bromide and active bromine were consistently elevated and ozone was depleted. Ozone depletion and active bromine enhancement were confined to the MBL that was capped by a temperature inversion at 200–500 m altitude. In ozone-depleted air, BrO rarely exceeded 10 pptv and was always substantially lower than soluble bromide that was as high as 40 pptv. BrCl was rarely enhanced above the 2 pptv detection limit, either in the MBL, over Alaska, or in the arctic free troposphere.

Department

Earth Sciences, Earth Systems Research Center

Publication Date

7-16-2010

Journal Title

Atmospheric Chemistry and Physics

Publisher

Copernicus Publications

Digital Object Identifier (DOI)

10.5194/acp-10-6503-2010

Document Type

Article

Recommended Citation

Neuman, J. A., Nowak, J. B., Huey, L. G., Burkholder, J. B., Dibb, J. E., Holloway, J. S., Liao, J., Peischl, J., Roberts, J. M., Ryerson, T. B., Scheuer, E., Stark, H., Stickel, R. E., Tanner, D. J., and Weinheimer, A.: Bromine measurements in ozone depleted air over the Arctic Ocean, Atmos. Chem. Phys., 10, 6503-6514, doi:10.5194/acp-10-6503-2010, 2010.

Rights

© Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 License.