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| Titel |
Ultraviolet absorption cross sections of isotopically substituted carbonyl sulfide species: OC32S, OC33S, OC34S, and O13CS |
| VerfasserIn |
Shohei Hattori, Sebastian O. Danielache, Matthew S. Johnson, Henrik Kjaergaard, Naohiro Yoshida |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250050268
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| Zusammenfassung |
| Carbonyl sulfide (OCS), a relatively inert tropospheric sulfur compound is thought to play an
important role as a source of background stratospheric sulfate aerosols (SSA). The main sink
for OCS in the stratosphere is photolysis which reaches 80% of the total chemical sink at
above 20 km; other sinks include reactions with O(3P) and OH. In order to investigate the
wavelength dependence of the photolytic kinetic isotope effect the absolute ultraviolet (UV)
absorption cross sections of OCS isotopologues OC32S, OC33S, and OC34S were measured
using labeled samples prepared in the laboratory. The observed cross section of OC32S is
consistent with previous reported cross sections of natural abundance samples. The peak
positions for labeled samples were shifted in a systematic way. Isotopologue absorptions
cross sections were not only shifted in energy but in intensity. In particular, the OC33S
isotopologue had the largest cross section of the measured OCS isotopologues. This finding
indicates that OCS photolysis may have a positive mass-independent effect on sulfur in
the stratosphere. Since OCS photolysis occurs in the lower stratospheric region,
integrated photolysis rates of each OCS isotopologues at 20 km are also discussed. |
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