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| Titel |
Constraints on inorganic gaseous iodine in the tropical upper troposphere and stratosphere inferred from balloon-borne solar occultation observations |
| VerfasserIn |
A. Butz, H. Bösch, C. Camy-Peyret, M. P. Chipperfield, M. Dorf, S. Kreycy, L. Kritten, C. Prados-Roman, J. Schwärzle, K. Pfeilsticker |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 9, no. 18 ; Nr. 9, no. 18 (2009-09-29), S.7229-7242 |
| Datensatznummer |
250007657
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| Publikation (Nr.) |
 copernicus.org/acp-9-7229-2009.pdf |
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| Zusammenfassung |
| We report upper limits of IO and OIO in the tropical upper
troposphere and stratosphere inferred from solar occultation spectra recorded
by the LPMA/DOAS (Limb Profile Monitor of the Atmosphere/Differential Optical
Absorption Spectroscopy) payload during two stratospheric balloon flights
from a station in Northern Brazil (5.1° S, 42.9° W). In the
tropical upper troposphere and lower stratosphere, upper limits for both,
IO and OIO, are below 0.1 ppt. Photochemical modelling
is used to estimate the compatible upper limits for the total gaseous
inorganic iodine burden (Iy) amounting to 0.09 to
0.16 (+0.10/−0.04) ppt in the tropical lower stratosphere
(21.0 km to 16.5 km) and 0.17 to
0.35 (+0.20/−0.08) ppt in the tropical upper troposphere
(16.5 km to 13.5 km). In the middle stratosphere, upper
limits increase with altitude as sampling sensitivity decreases. Our findings
imply that the amount of gaseous iodine transported into the stratosphere
through the tropical tropopause layer is small. Thus, iodine-mediated ozone
loss plays a minor role for contemporary stratospheric photochemistry but
might become significant in the future if source gas emissions or injection
efficiency into the upper atmosphere are enhanced. However,
photochemical modelling uncertainties are large and iodine might be
transported into the stratosphere in particulate form. |
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