Updates to the contribution of VSL species to stratospheric Bry

The Aura Ozone Monitoring Instrument (OMI) has provided global measurements of total column BrO over the past decade. To determine the impact of bromine on photochemical loss of atmospheric ozone, the contribution to total column BrO from the troposphere and stratosphere must be accurately assessed. In a 2010 study, Salawitch et al. recommended that an additional 5 to 10 ppt supply of very short lived (VSL) bromocarbons to stratospheric inorganic bromine (Bry­) is necessary to accurately represent the variation of total column BrO with total column O3. This recommendation will be reevaluated in light of total column BrO measurements obtained over Fairbanks, Alaska using a multifunction differential optical absorption spectroscopy (MFDOAS) instrument and the Pandora spectrometer system. Additionally, the impact of modifications to the kinetics regulating the partitioning between BrO and BrONO2 proposed by Kreycy et al. (2013) on the current VSL Bry estimate will be explored. Finally, we will evaluate the impact of our new understanding of VSL Bry on the tropospheric residual BrO that is inferred from OMI BrO.