Consistent Simulation of Bromine Chemistry From the Marine Boundary Layer to the Stratopause

Until recently, model studies of tropospheric bromine chemistry were performed with box or column models. To our knowledge, the only global model studies performed so far used chemical transport models (CTMs) and contained parameterised reactive halogen sources. In our approach, we avoid most of these assumptions. Using the atmospheric chemistry general circulation model ECHAM5/MESSy we simulate bromine chemistry consistently from the surface up to the stratopause. Emissions of sea salt aerosol as the largest surface source and the chemistry in both, the gas phase and the aerosol phase are calculated explicitly, leading to a fully prognostically determined bromine release from the aerosol into the gas phase. As an additional bromine source, we included ocean emissions of several bromocarbons. Their degradation by photolysis and stratospheric halogen chemistry are also part of the model setup.