Bromine atom production and chain propagation during springtime Arctic ozone depletion events in Barrow, Alaska

This work is a continuation of that presented in Thompson et al. (2015) and utilizes the same model construct. Here, we use the gas-phase radical chain length as a metric for objectively quantifying the efficiency of gas-phase recycling of bromine atoms. The gas-phase bromine chain length is de-termined to be quite small, at < 1.5, and highly dependent on ambient O-3 concentrations.

Furthermore, we find that Br atom production from photolysis of Br-2 and BrCl, which is predominately emitted from snow and/or aerosol surfaces, can account for between 30 and 90% of total Br atom production. This analysis suggests that condensed-phase production of bromine is at least as important as, and at times greater than, gas-phase recycling for the occurrence of Arctic ODEs. Therefore, the rate of the BrO self-reaction is not a sufficient estimate for the rate of O-3 depletion.