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Titel |
Aircraft based four-channel thermal dissociation laser induced fluorescence instrument for simultaneous measurements of NO2, total peroxy nitrate, total alkyl nitrate, and HNO3 |
VerfasserIn |
P. Carlo, E. Aruffo, M. Busilacchio, F. Giammaria, C. Dari-Salisburgo, F. Biancofiore, G. Visconti, J. Lee, S. Moller, C. E. Reeves, S. Bauguitte, G. Förster, R. L. Jones, B. Ouyang |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1867-1381
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Measurement Techniques ; 6, no. 4 ; Nr. 6, no. 4 (2013-04-12), S.971-980 |
Datensatznummer |
250017872
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Publikation (Nr.) |
copernicus.org/amt-6-971-2013.pdf |
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Zusammenfassung |
A four-channel thermal dissociation laser induced fluorescence (TD-LIF)
instrument has been developed for simultaneous measurements of nitrogen
dioxide (NO2), total peroxy nitrate (∑PNs), total alkyl nitrate
(∑ANs) and nitric acid (HNO3). NO2 is measured directly by
LIF at 532 nm, whereas organic nitrates and nitric acid are thermally
dissociated at distinct temperatures in the inlet to form NO2, which is
then measured by LIF. The concentrations of each dissociated species are
derived by the differences in measured NO2 relative to the reference
colder inlet channel. The TD-LIF was adapted to fly on board the UK Facility
for Airborne Atmospheric Measurements (FAAM) BAe 146-301 atmospheric
research aircraft in summer 2010, and to date has successfully flown in five
field campaigns. This paper reports novel improvements in the TD-LIF
instrumentations, including (1) the use of a single wavelength laser, which
makes the system compact and relatively cheap; (2) the use of a single beam
laser that allows easy alignment and optical stability against the
vibrational aircraft environment; and (3) the optical assembly of four
detection cells that allow simultaneous and fast (time resolution up to 0.1 s)
measurements of NO2, ∑PNs, ∑ANs and HNO3.
Laboratory-generated mixtures of PNs, ANs and HNO3 in zero air are
converted into NO2 and used to fix the dissociation temperatures of
each heated inlet to test the selectivity of the instrument and potential
interferences due to recombination reactions of the dissociated products.
The effectiveness of the TD-LIF was demonstrated during the RONOCO aircraft
campaign (summer 2010). A chemiluminescence system that was measuring
NO2 and a broadband cavity enhanced absorption spectrometer (BBCEAS)
that was measuring one of the PNs (N2O5) were installed on the
same aircraft during the campaign. The in-flight intercomparison of the new
TD-LIF with the chemiluminescence system for NO2 measurements and the
intercomparison between ∑PNs measured by the TD-LIF and N2O5
by the BBCEAS are used to assess the performance of the TD-LIF. |
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