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| Titel |
A novel method for measuring trace gas fluxes from tall vegetation |
| VerfasserIn |
James Keane, Phil Ineson |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250086915
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| Publikation (Nr.) |
 EGU/EGU2014-857.pdf |
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| Zusammenfassung |
| The nature of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) as greenhouse
gases (GHGs) means that accurate measurement of their net ecosystem exchange (NEE) is
extremely important to our ability to manage climate change. Manual static chambers are
commonly used to measure soil fluxes of these trace gases, with landscape values
extrapolated from point measurements of typically less than 1m2, at a weekly or monthly
frequency. Moreover, due to the reliance upon manual sampling, data are typically biased
towards day-time measurements, and use of opaque chambers halts photosynthesis.
Automation of chambers, such as the Licor Li-8100 (Lincoln, NE) system, allows for
measurement of soil respiration at a near-constant frequency, but does not solve the problem
of measuring CH4 and N2O, neither does it allow measurements to be taken from
over tall (more than 20 cm) vegetation. Eddy covariance (EC) techniques allow for
high frequency measurements of CO2 and CH4 to be made at the landscape scale,
and are increasingly available for N2O. However, the inability of EC to resolve to
the plot scale hinders its use for manipulative experiments, and replication is rare.
Additionally, stratification of the boundary layer creates difficulty in measuring night-time
fluxes and it is common to discard large parts of data sets due to unsuitable wind
direction or other meteorological conditions. Here we present a new technique
for measuring trace gas fluxes from over tall vegetation. The system is capable of
simultaneously delivering NEE of CO2, CH4 and N2O, automatically measuring at high
temporal resolution (circa hourly) from replicated plots. We show the effect of green
compost addition on trace gas fluxes from Miscanthus x giganteus, an important
crop for bioenergy production. The ability to quantify NEE of GHGs from such
crops forms an essential part of the lifecycle analysis of energy produced from
biomass, which may play an important role in future mitigation of climate change. |
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