Autocatalytic release of bromine from Arctic snow pack during polar sunrise
- Dept. of Phys. & Astron., York Univ., Ont. (Canada)
- Dept. of Earth & Atmos. Sci., York Univ., Ont. (Canada)
Measurements and modeling studies strongly suggest that spring time depletion of ozone in the Arctic planetary boundary layer (PBL) is due to catalytic destruction by bromine atoms. However, the source of the bromine is uncertain. In this note, we propose that the source of the bromine at polar sunrise is the snow pack on the ice covering Arctic ocean and that it is released auto-catalytically, stimulated by a bromine seed from one of the brominated organic compounds, such as CHBr{sub 3}, by photolysis. In this manner {approximately}100 pptv of bromine can be transferred to the atmosphere where it can reside in the gas phase or, by scavenging, be partitioned in the aerosol or ice crystal phase. Moreover, it appears that heterogeneous recycling of bromine may be a process that self-terminates as ozone depletes to low levels. We also have included chlorine chemistry in the model in order to simulate inferred levels of chlorine atoms. This is important as it results in the production of HCHO which acts to convert post ozone depletion active bromine into HBr which is then returned to the snow pack or scavenged by aerosols or ice crystals. {copyright} American Geophysical Union 1996
- OSTI ID:
- 404015
- Journal Information:
- Geophysical Research Letters, Vol. 23, Issue 19; Other Information: PBD: Sep 1996
- Country of Publication:
- United States
- Language:
- English
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