- 1Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, M3H 5T4, Canada
- 2Department of Environmental Science, iClimate, ARC, Aarhus University, Roskilde, 4000, Denmark
- 3Research Institute for Global Change (RIGC), Japan Agency for Marine–Earth Science and Technology (JAMSTEC), Yokohama 2360001, Japan
- 4Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Blas Cabrera, CSIC, Madrid, 28006, Spain
- 5School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- 6School of Chemistry, University of Leicester, Leicester, UK
- 7Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, 80309, USA
- 8National Oceanic and Atmospheric Administration Global Monitoring Laboratory, Boulder, CO 80305, USA
- 9Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York YO10 5DD, United Kingdom
- 10Danish Meteorological Institute, 2100 Copenhagen, Denmark
- 11Space and Earth Observation Centre, Finnish Meteorological Institute, Tähteläntie 62, 99600 Sodankylä, Finland
- 12Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong 999077
- 13Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research, Telegrafenberg A43, 14473 Potsdam, Germany
- *A full list of authors appears at the end of the abstract
A large portion of the Arctic is covered by ocean and sea ice, from which reactive halogen species can be emitted to the atmosphere. Springtime ozone depletion events (ODEs) have been primarily attributed to catalytic destruction of ozone by reactive bromine released from snowpacks and blowing snow over sea ice and cycled through heterogeneous reactions on aerosol surfaces. Mechanisms to represent polar springtime bromine explosions and ODEs have been developed and tested in various atmospheric models, by considering both blowing snow and snowpacks, with varying degrees of success when compared with observations of reactive bromine and ozone in polar regions. In this study, two independent chemical transport models (CTMs), DEHM (Danish Eulerian Hemispheric Model) and GEM-MACH (Global Environmental Multi-scale – Modelling Air quality and Chemistry), were used to simulate Arctic lower tropospheric ozone for the year 2015. Both models include bromine chemistry and a representation of snow-sourced bromine mechanism: a blowing-snow bromine source mechanism in DEHM and a snowpack bromine source mechanism in GEM-MACH.
The comparison of model simulation results with available observations in the Arctic showed that the model with the snowpack bromine source mechanism (GEM-MACH) was able to capture most of the observed springtime ODEs in the Arctic, while the model considering blowing-snow sourced bromine alone (DEHM) simulated much fewer ODEs. The snowpack-sourced mechanism is seen to be essential in sustaining the continued bromine production under a variety of meteorological conditions, while the blowing-snow bromine source mechanism triggered by high wind conditions tends to be more episodic. This is consistent with observational evidence that the ODEs observed in the Arctic tend to occur during calm wind conditions favouring the snowpack bromine source mechanism to take effect in the surface air with ODEs at high wind speed conditions to occur sporadically. The study demonstrated that the springtime ozone depletion process plays a central role in driving the surface ozone seasonal cycle in the Central Arctic, and that the bromine-mediated ODEs, while occurring most notably within the lowest few hundred metres of air above the Arctic Ocean, can induce a 5-7% of loss in the total pan-Arctic tropospheric ozone burden during springtime. The study also demonstrated that atmospheric aerosols play an integral role in the Arctic springtime bromine explosions and ODEs through heterogeneous cycling of reactive bromine, particularly over a deeper vertical layer and at distance from the snowpack bromine source area, which has implications for the potential role of Arctic haze aerosols that may play in the springtime ODEs. The uncertainty in parameterising the Arctic bromine source mechanism will also be discussed.
Wanmin Gong1, Stephen R. Beagley1, Kenjiro Toyota1, Henrik Skov2, Jesper Heile Christensen2, Alex Lupu1, Diane Pendlebury1, Junhua Zhang1, Ulas Im2, Yugo Kanaya3, Alfonso Saiz-Lopez4, Roberto Sommariva5,6, Peter Effertz7,8, John W. Halfacre9, Nis Jepsen10, Rigel Kivi11, Theodore K. Koenig12, Katrin Müller13, Claus Nordstrøm2, Irina Petropavlovski7,8, Paul B. Shepson14, William R. Simpson15, Sverre Solberg16, Ralf M. Staebler1, David W. Tarasick1, Roeland Van Malderen17, Mika Vestenius18
How to cite: Gong, W., Beagley, S., Toyota, K., Skov, H., Christensen, J., Lupu, A., Pendlebury, D., Zhang, J., Im, U., Kanaya, Y., Saiz-Lopez, A., Sommariva, R., Effertz, P., Halfacre, J., Jepsen, N., Kivi, R., Koenig, T., Müller, K., Nordstrøm, C., and Petropavlovski, I. and the TOAR-II Ozone Over the Oceans Focus Working Group - Arctic: Modelling Arctic springtime ozone depletion events: role of snow sourced bromine chemistry and its impact on Arctic tropospheric ozone budget, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7049, https://doi.org/10.5194/egusphere-egu25-7049, 2025.
