Journal cover Journal topic
Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
Geosci. Model Dev., 11, 1115-1131, 2018
https://doi.org/10.5194/gmd-11-1115-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
Development and technical paper
28 Mar 2018
Polar boundary layer bromine explosion and ozone depletion events in the chemistry–climate model EMAC v2.52: implementation and evaluation of AirSnow algorithm
Stefanie Falk1,a and Björn-Martin Sinnhuber1 1Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany
anow at: Department of Geosciences, University of Oslo, Oslo, Norway
Abstract. Ozone depletion events (ODEs) in the polar boundary layer have been observed frequently during springtime. They are related to events of boundary layer enhancement of bromine. Consequently, increased amounts of boundary layer volume mixing ratio (VMR) and vertical column densities (VCDs) of BrO have been observed by in situ observation, ground-based as well as airborne remote sensing, and from satellites. These so-called bromine explosion (BE) events have been discussed serving as a source of tropospheric BrO at high latitudes, which has been underestimated in global models so far. We have implemented a treatment of bromine release and recycling on sea-ice- and snow-covered surfaces in the global chemistry–climate model EMAC (ECHAM/MESSy Atmospheric Chemistry) based on the scheme of Toyota et al. (2011). In this scheme, dry deposition fluxes of HBr, HOBr, and BrNO3 over ice- and snow-covered surfaces are recycled into Br2 fluxes. In addition, dry deposition of O3, dependent on temperature and sunlight, triggers a Br2 release from surfaces associated with first-year sea ice. Many aspects of observed bromine enhancements and associated episodes of near-complete depletion of boundary layer ozone, both in the Arctic and in the Antarctic, are reproduced by this relatively simple approach. We present first results from our global model studies extending over a full annual cycle, including comparisons with Global Ozone Monitoring Experiment (GOME) satellite BrO VCDs and surface ozone observations.
Citation: Falk, S. and Sinnhuber, B.-M.: Polar boundary layer bromine explosion and ozone depletion events in the chemistry–climate model EMAC v2.52: implementation and evaluation of AirSnow algorithm, Geosci. Model Dev., 11, 1115-1131, https://doi.org/10.5194/gmd-11-1115-2018, 2018.
Publications Copernicus
Download
Short summary
Ozone depletion events (ODEs) in the polar boundary layer are observed frequently in spring. ODEs serve as a source of tropospheric BrO at high latitudes. A treatment of bromine release and recycling on sea-ice- and snow-covered surfaces is implemented in global chemistry–climate model EMAC based on a scheme of Toyota et al. (2011). Many aspects of bromine enhancement and associated ODEs are reproduced in both polar regions. Further bromine release mechanisms can now be tested in a global model.
Ozone depletion events (ODEs) in the polar boundary layer are observed frequently in spring....
Share