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Chlorine chemistry in the Antarctic stratosphere: Impact of OClO and Cl 2 O 2 and implications for observations
Author(s) -
Rodriguez José M.,
Ko Malcolm K. W.,
Dak Sze Nien
Publication year - 1986
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl013i012p01292
Subject(s) - chlorine , stratosphere , bromine , chlorofluorocarbon , chemistry , catalysis , yield (engineering) , atmospheric chemistry , atmospheric sciences , halogen , environmental chemistry , ozone , thermodynamics , physics , organic chemistry , alkyl
Theories have been proposed to relate the reduction of O 3 during antarctic spring to catalytic cycles involving chlorine and bromine species. A necessary condition for any chlorine‐catalyzed scheme is that a large fraction of the chlorine must be in the form of ClO in the lower stratosphere. It has been suggested that these high levels of ClO could be maintained by fast heterogeneous reactions, whose rates are not known at present. Model calculations based on the above mechanisms predict considerable amounts of OClO and Cl 2 O 2 , particularly during the night. We present results of calculations of the diurnal variations of ClO, OClO, and Cl 2 O 2 during antarctic spring, for different cases. Results from our calculations suggest that coincident measurements of the total column abundance and diurnal variation of ClO and OClO may help constrain key aspects of the proposed chemical mechanisms. Removal of O 3 by the catalytic cycle involving Cl 2 O 2 could be as important as that involving BrO for present levels of chlorine, provided that Cl 2 O 2 photolyzes rapidly to yield Cl and ClO 2 . We show that there is no synergy between these two cycles, since they both compete for the available ClO.