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Increase in levels of stratospheric chlorine and fluorine loading between 1985 and 1992
Author(s) -
Gunson M. R.,
Abrams M. C.,
Lowes L. L.,
Mahieu E.,
Zander R.,
Rinsland C. P.,
Ko M. K. W.,
Sze N. D.,
Weisenstein D. K.
Publication year - 1994
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 - 10.1029/94gl02077
Subject(s) - chlorine , stratosphere , ozone , mixing ratio , atmospheric chemistry , parts per notation , ozone layer , atmospheric sciences , isotopes of chlorine , ozone depletion , environmental science , chlorofluorocarbon , fluorine , trace gas , environmental chemistry , chemistry , meteorology , physics , organic chemistry
Mixing ratios of 3.44 ppbv (parts per billion by volume) and 1.23 ppbv for HCl and HF above 50 km, surrogates for total chlorine and fluorine, have been measured by the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment on a March 1992 flight of the Space Shuttle. Compared to the measured values obtained on a 1985 flight, these correspond to a 37% and 62% increase for HCl and HF, respectively. The derived trend in HCl (∼0.13 ppbv per year) is in good agreement with the model‐predicted increase in chlorine loading of 0.13 ppbv per year [ Prather and Watson, 1990], and with the measured trends in HCl total column abundance from reported ground‐based observations. The main source of this change can be attributed to the release of man‐made chlorofluorocarbons (CFCs) and hydrochloro‐fluorocarbons (HCFCs). This new value for HCl represents an upper limit to the inorganic chlorine concentration in the stratosphere available for participation in photochemical processes which destroy ozone.