STRATOSPHERIC HBR CONCENTRATION PROFILE OBTAINED FROM FAR-INFRARED EMISSION-SPECTROSCOPY

Hydrogen bromide (HBr) is the principal bromine sink species for the o zone loss chemistry induced by bromine-containing gases in the stratos phere. We report a 1994 balloon-based measurement of the daytime strat ospheric HBr profile between 20 and 36.5 km altitude. The average conc entration result of 1.31 +/- 0.39 parts per trillion in volume (pptv) and an analysis for the concentration versus altitude profile are cons istent with previously reported measurements. These results strengthen the evidence for a significantly higher HBr concentration than that p redicted by current photochemical models which, on the basis of recent kinetics results, do not include significant HBr production by the re action branch, BrO + HO2 --> HBr + O-3.