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Transfer of mass‐independent fractionation in ozone to other oxygen‐containing radicals in the atmosphere
Author(s) -
Lyons James R.
Publication year - 2001
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 - 10.1029/2000gl012791
Subject(s) - stratosphere , troposphere , radical , ozone , atmosphere (unit) , chemistry , oxygen , atmospheric chemistry , atmospheric sciences , yield (engineering) , mass independent fractionation , fractionation , photochemistry , reaction rate constant , environmental chemistry , meteorology , kinetics , thermodynamics , physics , organic chemistry , isotope fractionation , quantum mechanics
Mass‐independent fractionation (MIF) of ozone has been observed in both the troposphere and stratosphere. Because ozone is a photochemically active species, its MIF signature can be imparted to other atmospheric molecules. Using a photochemical equilibrium model for short‐lived radical species, I have computed the expected MIF for typical mid‐latitude conditions. The model accounts for about ∼70% of recent measurements of Δ 17 7O for H 2 O 2 in rainwater, and predicts large MIF for NO x and ClO species (∼40–70‰), and their products (ClONO 2 and HNO 3 ). Furthermore, in the stratosphere oxygen exchange reactions between OH and NO x yield OH with Δ 17 O from 2 to 45‰. Stratospheric water produced during H abstraction by OH would be similarly mass‐independently fractionated. In the troposphere rapid exchange between OH and H 2 O erases any MIF signature in OH. These model results depend on several O exchange reactions with unknown activation energies or with rate coefficients known only as upper limits.