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| Titel |
Feasibility study of using a "travelling" CO2 and CH4 instrument to validate continuous in situ measurement stations |
| VerfasserIn |
S. Hammer, G. Konrad, A. T. Vermeulen, O. Laurent, M. Delmotte, A. Jordan, L. Hazan, S. Conil, I. Levin |
| 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. 5 ; Nr. 6, no. 5 (2013-05-14), S.1201-1216 |
| Datensatznummer |
250017888
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| Publikation (Nr.) |
 copernicus.org/amt-6-1201-2013.pdf |
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| Zusammenfassung |
| In the course of the ICOS (Integrated Carbon Observation System)
Demonstration Experiment a feasibility study on the usefulness of a
travelling comparison instrument (TCI) was conducted in order to evaluate
continuous atmospheric CO2 and CH4 measurements at two European
stations. The aim of the TCI is to independently measure ambient air in
parallel to the standard station instrumentation, thus providing a
comprehensive comparison that includes the sample intake system, the
instrument itself as well as its calibration and data evaluation. Observed
differences between the TCI and a gas chromatographic system, which acted as
a reference for the TCI, were −0.02 ± 0.08 μmol mol−1
for CO2 and −0.3 ± 2.3 nmol mol−1 for CH4. Over
a period of two weeks each, the continuous CO2 and CH4 measurements
at two ICOS field stations, Cabauw (CBW), the Netherlands and Houdelaincourt
(Observatoire Pérenne de l'Environnement, OPE), France, were compared to
co-located TCI measurements. At Cabauw mean differences of
0.21 ± 0.06 μmol mol−1 for CO2 and
0.41 ± 0.50 nmol mol−1 for CH4 were found. For OPE the
mean differences were 0.13 ± 0.07 μmol mol−1 for
CO2 and 0.44 ± 0.36 nmol mol−1 for CH4. Offsets
arising from differences in the working standard calibrations or
leakages/contaminations in the drying systems are too small to explain the
observed differences. Hence the most likely causes of these observed
differences are leakages or contaminations in the intake lines and/or their
flushing pumps. For the Cabauw instrument an additional error contribution
originates from insufficient flushing of standard gases. Although the TCI is
an extensive quality control approach it cannot replace other quality control
systems. Thus, a comprehensive quality management strategy for atmospheric
monitoring networks is proposed as well. |
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