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| Titel |
Intercomparison of gas analyzers for methane flux measurements |
| VerfasserIn |
Sami Haapanala, Janne Rinne, Olli Peltola, Ivan Mammarella, Timo Vesala |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051127
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| Zusammenfassung |
| During the last years there has been a rapid development in application of laser spectroscopy
for greenhouse gas measurements. Four gas analyzers, capable of measuring methane
concentration at a response time necessary for eddy covariance flux measurements, were
operated in parallel for about six months between March and August 2010. Their reliability,
need of maintenance, user friendliness, data coverage, and data quality were evaluated.
The primary aim of this campaign was to provide an instrumentation suggestion
for the European Research Infrastructure ICOS (Integrated Carbon Observation
System). In addition, methods for flux calculation using laser spectrometer data were
evaluated.
The instruments used were TGA100A (Campbell Scientific Inc.), RMT-200 (Los Gatos
Research Inc.), G1301-f (Picarro Inc.), and LI-7700 (Li-Cor Inc.). The last one, LI-7700, was
a prototype of a later commercialized open path analyzer. The other instruments were closed
path analyzers.
The measurement site is an oligotrophic open fen Siikaneva, located in southern Finland.
The site provides spatially quite uniform methane flux within the footprint. The methane flux
rises in the spring, peaks in early August and falls down during the autumn. This provides
excellent opportunity to study the performance of the analyzers at different CH4 flux levels
from near zero up to over 5 mg m-2 h-1.
The results show great similarity among the instruments in both concentrations and
fluxes. Detailed numbers of the measurement characteristics will be provided. Suitability of
the instruments for specific purposes will be discussed. There were some differences between
the instruments in reliability and need on maintenance. However, these are difficult to
evaluate quantitatively during that short period, and using just one instrument of a kind. |
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