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| Titel |
Technical Note: Formal blind intercomparison of HO2 measurements in the atmosphere simulation chamber SAPHIR during the HOxComp campaign |
| VerfasserIn |
H. Fuchs, T. Brauers, H.-P. Dorn, H. Harder, R. Häseler, A. Hofzumahaus, F. Holland, Y. Kanaya, Y. Kajii, D. Kubistin, S. Lou, M. Martinez, K. Miyamoto, S. Nishida, M. Rudolf, E. Schlosser, A. Wahner, A. Yoshino, U. Schurath |
| 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. 24 ; Nr. 10, no. 24 (2010-12-23), S.12233-12250 |
| Datensatznummer |
250008977
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| Publikation (Nr.) |
 copernicus.org/acp-10-12233-2010.pdf |
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| Zusammenfassung |
| Hydroperoxy radical (HO2) concentrations were measured during the
formal blind intercomparison campaign HOxComp carried out in Jülich,
Germany, in 2005. Three instruments detected HO2 via chemical
conversion to hydroxyl radicals (OH) and subsequent detection of the
sum of OH and HO2 by laser induced fluorescence (LIF). All
instruments were based on the same detection and calibration scheme. Because
measurements by a MIESR instrument failed during the campaign, no absolute
reference measurement was available, so that the accuracy of individual
instruments could not be addressed. Instruments sampled ambient air for three
days and were attached to the atmosphere simulation chamber SAPHIR during the
second part of the campaign. Six experiments of one day each were conducted
in SAPHIR, where air masses are homogeneously mixed, in order to investigate
the performance of instruments and to determine potential interferences of
measurements under well-controlled conditions. Linear correlation
coefficients (R2) between measurements of the LIF instruments are
generally high and range from 0.82 to 0.98. However, the agreement between
measurements is variable. The regression analysis of the entire data set of
measurements in SAPHIR yields slopes between 0.69 to 1.26 and intercepts are
smaller than typical atmospheric daytime concentrations (less than
1 pptv). The quality of fit parameters improves significantly, when
data are grouped into data subsets of similar water vapor concentrations.
Because measurements of LIF instruments were corrected for a
well-characterized water dependence of their sensitivities, this indicates
that an unknown factor related to water vapor affected measurements in
SAPHIR. Measurements in ambient air are also well-correlated, but regression
parameters differ from results obtained from SAPHIR experiments. This could
have been caused by differences in HO2 concentrations in the sampled
air at the slightly different locations of instruments. |
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