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Titel |
The spatial distribution of the reactive iodine species IO from simultaneous active and passive DOAS observations |
VerfasserIn |
K. Seitz, J. Buxmann, D. Pöhler, T. Sommer, J. Tschritter, T. Neary, C. O'Dowd, U. Platt |
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 ; 10, no. 5 ; Nr. 10, no. 5 (2010-03-01), S.2117-2128 |
Datensatznummer |
250008159
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Publikation (Nr.) |
copernicus.org/acp-10-2117-2010.pdf |
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Zusammenfassung |
We present investigations of the reactive iodine species (RIS) IO,
OIO and I2 in a coastal region from a field campaign
simultaneously employing active long path differential optical
absorption spectroscopy (LP-DOAS) as well as passive multi-axis
differential optical absorption spectroscopy (MAX-DOAS). The
campaign took place at the Martin Ryan Institute (MRI) in Carna,
County Galway at the Irish West Coast about 6 km south-east of
the atmospheric research station Mace Head in summer 2007. In
order to study the horizontal distribution of the trace gases of
interest, we established two almost parallel active LP-DOAS light
paths, the shorter of 1034 m length just crossing the intertidal
area, whereas the longer one of 3946 m length also crossed open
water during periods of low tide. In addition we operated two
passive Mini-MAX-DOAS instruments with the same viewing direction.
While neither OIO nor I2 could be unambiguously identified with
any of the instruments, IO could be detected with active as well
as passive DOAS. The IO column densities seen at both active
LP-DOAS light paths are almost the same. Thus it can be concluded
that coastal IO is almost exclusively located in the intertidal
area, where we detected mixing ratios of up to 29±8.8 ppt
(equivalent to pmol/mol). Nucleation events with particle
concentrations of 106 cm−3 particles were observed each
day correlating with high IO mixing ratios. Therefore we feel that
our detected IO concentrations confirm the results of model
studies, which state that in order to explain such particle
bursts, IO mixing ratios of 50 to 100 ppt in so called
"hot-spots" are required. |
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