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| Titel |
Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic Plateau) in summer: a strong source from surface snow? |
| VerfasserIn |
M. Legrand, S. Preunkert, M. Frey, Thorsten Bartels-Rausch, A. Kukui, M. D. King, J. Savarino, M. Kerbrat, B. Jourdain |
| 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 ; 14, no. 18 ; Nr. 14, no. 18 (2014-09-19), S.9963-9976 |
| Datensatznummer |
250119052
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| Publikation (Nr.) |
 copernicus.org/acp-14-9963-2014.pdf |
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| Zusammenfassung |
| During the austral summer 2011/2012 atmospheric nitrous acid (HONO) was
investigated for the second time at the Concordia site (75°06' S,
123°33' E), located on the East Antarctic Plateau, by deploying a
long-path absorption photometer (LOPAP). Hourly mixing ratios of HONO
measured in December 2011/January 2012 (35 ± 5.0 pptv) were similar to
those measured in December 2010/January 2011 (30.4 ± 3.5 pptv). The
large value of the HONO mixing ratio at the remote Concordia site suggests a
local source of HONO in addition to weak production from oxidation of NO by
the OH radical. Laboratory experiments demonstrate that surface snow removed
from Concordia can produce gas-phase HONO at mixing ratios half that of
the NOx mixing ratio produced in the same experiment at typical
temperatures encountered at Concordia in summer. Using these lab data and
the emission flux of NOx from snow estimated from the vertical gradient
of atmospheric concentrations measured during the campaign, a mean diurnal
HONO snow emission ranging between 0.5 and 0.8 × 109 molecules
cm−2 s−1 is calculated. Model calculations indicate that, in addition to
around 1.2 pptv of HONO produced by the NO oxidation, these HONO snow
emissions can only explain 6.5 to 10.5 pptv of HONO in the atmosphere at
Concordia. To explain the difference between observed and simulated HONO
mixing ratios, tests were done both in the field and at lab to explore the
possibility that the presence of HNO4 had biased the measurements of
HONO. |
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