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| Titel |
The "Lung": a software-controlled air accumulator for quasi-continuous multi-point measurement of agricultural greenhouse gases |
| VerfasserIn |
R. J. Martin, A. M. Bromley, M. J. Harvey, R. C. Moss, E. Pattey, D. Dow |
| 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 ; 4, no. 10 ; Nr. 4, no. 10 (2011-10-21), S.2293-2303 |
| Datensatznummer |
250002124
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| Publikation (Nr.) |
 copernicus.org/amt-4-2293-2011.pdf |
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| Zusammenfassung |
We describe the design and testing of a flexible bag ("Lung") accumulator
attached to a gas chromatographic (GC) analyzer capable of measuring
surface-atmosphere greenhouse gas exchange fluxes in a wide range of
environmental/agricultural settings. In the design presented here, the
Lung can collect up to three gas samples concurrently, each accumulated into
a Tedlar bag over a period of 20 min or longer.
Toggling collection between 2 sets of 3 bags enables quasi-continuous
collection with sequential analysis and discarding of sample residues. The
Lung thus provides a flexible "front end" collection system for
interfacing to a GC or alternative analyzer and has been used in 2 main
types of application. Firstly, it has been applied to micrometeorological
assessment of paddock-scale N2O fluxes, discussed here. Secondly, it
has been used for the automation of concurrent emission assessment from
three sheep housed in metabolic crates with gas tracer addition and sampling
multiplexed to a single GC.
The Lung allows the same GC equipment used in laboratory discrete sample
analysis to be deployed for continuous field measurement. Continuity of
measurement enables spatially-averaged N2O fluxes in particular to be
determined with greater accuracy, given the highly heterogeneous and
episodic nature of N2O emissions. We present a detailed evaluation of
the micrometeorological flux estimation alongside an independent tuneable
diode laser system, reporting excellent agreement between flux estimates
based on downwind vertical concentration differences. Whilst the current
design is based around triplet bag sets, the basic design could be scaled up
to a larger number of inlets or bags and less frequent analysis (longer
accumulation times) where a greater number of sampling points are required. |
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