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Titel |
Gas adsorption and desorption effects on high pressure small volume cylinders and their relevance to atmospheric trace gas analysis |
VerfasserIn |
Ece Satar, Peter Nyfeler, Céline Pascale, Bernhard Niederhauser, Markus Leuenberger |
Konferenz |
EGU General Assembly 2017
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Medientyp |
Artikel
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Sprache |
en
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 19 (2017) |
Datensatznummer |
250150530
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Publikation (Nr.) |
EGU/EGU2017-15002.pdf |
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Zusammenfassung |
Long term atmospheric monitoring of trace gases requires great attention to precision and
accuracy of the measurement setups. For globally integrated and well established greenhouse
gas observation networks, the World Meteorological Organization (WMO) has set
recommended compatibility goals within the framework of its Global Atmosphere Watch
(GAW) Programme [1]. To achieve these challenging limits, the measurement systems are
regularly calibrated with standard gases of known composition. Therefore, the stability of the
primary and secondary gas standards over time is an essential issue. Past studies have
explained the small instabilities in high pressure standard gas cylinders through leakage,
diffusion, regulator effects, gravimetric fractionation and surface processes [2, 3]. The latter
include adsorption/desorption, which are functions of temperature, pressure and
surface properties. For high pressure standard gas mixtures used in atmospheric
trace gas analysis, there exists only a limited amount of data and few attempts to
quantify the surface processes [4, 5]. Specifically, we have designed a high pressure
measurement chamber to investigate trace gases and their affinity for adsorption on
different surfaces over various temperature and pressure ranges. Here, we focus
on measurements of CO2, CH4 and CO using a cavity ring down spectroscopy
analyzer and quantify the concentration changes due to adsorption/desorption. In this
study, the first results from these prototype cylinders of steel and aluminum will be
presented.
References
[1] World Meteorological Organization (WMO), Global Atmosphere Watch.(GAW):
Report No. 229, 18th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases
and Related Tracers Measurement Techniques (GGMT-2015), 2016.
[2] Keeling, R. F., Manning, A. C., Paplawsky, W. J., and Cox, A. C.: On the long-term
stability of reference gases for atmospheric O2 /N2 and CO2 measurements, Tellus B, 59,
10.3402/tellusb.v59i1.16964, 2007.
[3] Langenfelds, R. L., van der Schoot, M. V., Francey, R. J., Steele, L. P., Schmidt, M.,
and Mukai, H.: Modification of air standard composition by diffusive and surface processes,
Journal of Geophysical Research: Atmospheres, 110, n/a-n/a, 10.1029/2004JD005482,
2005.
[4] Leuenberger, M. C., Schibig, M. F., and Nyfeler, P.: Gas adsorption and desorption
effects on cylinders and their importance for long-term gas records, Atmos. Meas. Tech., 8,
5289-5299, 10.5194/amt-8-5289-2015, 2015
[5] Miller, W. R., Rhoderick, G. C., and Guenther, F. R.: Investigating Adsorption/Desorption
of Carbon Dioxide in Aluminum Compressed Gas Cylinders, Analytical Chemistry, 87,
1957-1962, 10.1021/ac504351b, 2015. |
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