Ozone depletion events in the polar troposphere have been linked to extremely high concentrations of bromine, known as bromine explosion events (BEE). However, the optimum meteorological conditions for the occurrence of these events remain uncertain. On 4–5 April 2011, a combination of both blowing snow and a stable shallow boundary layer was observed during a BEE at Eureka, Canada (86.4°W, 80.1°N). Measurements made by a Multi-Axis Differential Optical Absorption Spectroscopy spectrometer were used to retrieve BrO profiles and partial columns. During this event, the near-surface BrO volume mixing ratio increased to ~20 parts per trillion by volume, while ozone was depleted to ~1 ppbv from the surface to 700 m. Back trajectories and Global Ozone Monitoring Experiment-2 satellite tropospheric BrO columns confirmed that this event originated from a bromine explosion over the Beaufort Sea. From 30 to 31 March, meteorological data showed high wind speeds (24 m/s) and elevated boundary layer heights (~800 m) over the Beaufort Sea. Long-distance transportation (~1800 km over 5 days) to Eureka indicated strong recycling of BrO within the bromine plume. This event was generally captured by a global chemistry-climate model when a sea-salt bromine source from blowing snow was included. A model sensitivity study indicated that the surface BrO at Eureka was controlled by both local photochemistry and boundary layer dynamics. Comparison of the model results with both ground-based and satellite measurements confirmed that the BEE observed at Eureka was triggered by transport of enhanced BrO from the Beaufort Sea followed by local production/recycling under stable atmospheric shallow boundary layer conditions.
Bibliographical noteFunding Information:
The authors gratefully acknowledge the support from CANDAC funding agencies: ARIF, AIF/NSRIT, CFCAS, CFI, CSA, EC, GOC-IPY, INAC, NSERC, NSTP, OIT, ORF, PCSP, and SEARCH. We thank CANDAC/PEARL PI James R. Drummond, PEARL site manager Pierre Fogal, the CANDAC operators, and Environment Canada Eureka Weather Station staff for logistical and operational support at Eureka. The spring 2011 PEARL-GBS measurements were also supported by the Canadian Arctic ACE Validation Campaigns (Co-PI Kaley Walker), which were funded by Canadian Space Agency. The PEARL-GBS and MMCR data are available from CANDAC (http://www.candac.ca). The ozonesonde and radiosonde data for this paper are available through the Canadian Arctic ACE Validation Campaigns http://acebox.uwaterloo.ca/eureka/Eureka2011/). Any additional data may be obtained from Xiaoyi Zhao (email: email@example.com). X. Zhao is partially supported by the NSERC CREATE Training Programin Arctic Atmospheric Science. R. Schofield received funding support for this work from the Australian Research Councils Centre of Excellence (CE110001028) scheme. Ozonesonde, radiosonde, and MMCR measurements were provided by David Tarasick, David Hudak, and Peter Rodriguez at Environment Canada. The QDOAS software and AMFs were provided by C. Fayt, F. Hendrick, and M. Van Roozendael at IASB-BIRA. Many thanks to Alexei Rozanov from IUP Bremen for providing the SCIATRAN radiative transfer model. We also want to thank Paul Telford and John Pyle at the University of Cambridge for supporting the UM-UKCA model integration. We thank the NSIDC, University of Colorado, the NOAA Air Resources Laboratory, and the ECMWF for providing data sets andmodels. NCEP Reanalysis data were provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado.
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All Science Journal Classification (ASJC) codes
- Aquatic Science
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth-Surface Processes
- Atmospheric Science
- Space and Planetary Science
- Earth and Planetary Sciences (miscellaneous)