Global observations of stratospheric bromine monoxide from SCIAMACHY

The Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) onboard the ENVISAT satellite provides for the first time a global view on stratospheric bromine monoxide (BrO). Here we focus on a 10 day period in September 2002. The BrO retrievals are compared with modeled BrO profiles, based on estimated inorganic bromine (Bry) from CFC‐11 retrievals by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on ENVISAT and the calculated BrO/Bry ratio from a photochemical model constrained by SCIAMACHY NO2 retrievals. The BrO observations are broadly consistent with our current understanding of stratospheric bromine chemistry and a total stratospheric bromine loading of 18 ± 3 pptv. Comparisons between the measured stratospheric BrO column and the simultaneously measured total BrO column from SCIAMACHY nadir observations suggest an average global background tropospheric BrO mixing ratio of 1.0 ± 0.5 pptv.