Stratospheric HBr concentration profile obtained from farinfrared emission spectroscopy

Hydrogen bromide (HBr) is the principal bromine sink species for the ozone loss chemistry induced by brominecontaining ases in the stratosphere. We report a 1994 balloon-based measurement of the daytime stratospherie HBr profile between 20 and 36.5 km altitude. The average concentration result of 1.31 + 0.39 parts per trillion in volume (pptv) and an analysis for the concentration versus altitude profile are consistent with previously reported measurements. These results strengthen the evidence for a significantly higher H]3r concentration than that predicted by current photochemical models which, on the basis of recent kinetics results, do not include significant Hl3r production by the reaction branch, BrO + HO2 --) HBr + 03.