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| Titel |
Observations of OH and HO2 radicals in coastal Antarctica |
| VerfasserIn |
W. J. Bloss, J. D. Lee, D. E. Heard, R. A. Salmon, S. J.-B. Bauguitte, H. K. Roscoe, A. E. Jones |
| 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 ; 7, no. 16 ; Nr. 7, no. 16 (2007-08-16), S.4171-4185 |
| Datensatznummer |
250005161
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| Publikation (Nr.) |
 copernicus.org/acp-7-4171-2007.pdf |
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| Zusammenfassung |
| OH and HO2 radical concentrations have been measured in the boundary
layer of coastal Antarctica for a six-week period during the austral summer
of 2005. The measurements were performed at the British Antarctic Survey's
Halley Research Station (75° 35' S, 26° 19' W), using the technique
of on-resonance laser-induced fluorescence to detect OH, with HO2
measured following chemical conversion through addition of NO. The mean
radical levels were 3.9×105 molecule cm−3 for OH, and
0.76 ppt for HO2 (ppt denotes parts per trillion, by volume). Typical
maximum (local noontime) levels were 7.9×105 molecule cm−3
and 1.50 ppt for OH and HO2 respectively. The main sources of HOx
were photolysis of O3 and HCHO, with potentially important but
uncertain contributions from HONO and higher aldehydes. Of the measured OH
sinks, reaction with CO and CH4 dominated, however comparison of the
observed OH concentrations with those calculated via the steady state
approximation indicated that additional co-reactants were likely to have
been present. Elevated levels of NOx resulting from snowpack
photochemistry contributed to HOx cycling and enhanced levels of OH,
however the halogen oxides IO and BrO dominated the CH3O2 –
HO2 – OH conversion in this environment, with associated ozone
destruction. |
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