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Titel |
Evaluation of a plot-scale methane emission model using eddy covariance observations and footprint modelling |
VerfasserIn |
A. Budishchev, Y. Mi, J. van Huissteden, L. Belelli-Marchesini, G. Schaepman-Strub, F. J. W. Parmentier, G. Fratini, A. Gallagher, T. C. Maximov, A. J. Dolman |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 11, no. 17 ; Nr. 11, no. 17 (2014-09-03), S.4651-4664 |
Datensatznummer |
250117575
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Publikation (Nr.) |
copernicus.org/bg-11-4651-2014.pdf |
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Zusammenfassung |
Most plot-scale methane emission models – of which many have been
developed in the recent past – are validated using data collected
with the closed-chamber technique. This method, however, suffers
from a low spatial representativeness and a poor temporal
resolution. Also, during a chamber-flux measurement the air within
a chamber is separated from the ambient atmosphere, which negates
the influence of wind on emissions.
Additionally, some methane models are validated by upscaling fluxes
based on the area-weighted averages of modelled fluxes,
and by comparing those to the eddy covariance (EC) flux. This
technique is rather inaccurate, as the area of upscaling might be
different from the EC tower footprint, therefore introducing
significant mismatch.
In this study, we present an approach to validate plot-scale methane
models with EC observations using the footprint-weighted average
method. Our results show that the fluxes obtained by the
footprint-weighted average method are of the same magnitude as the
EC flux. More importantly, the temporal dynamics of the EC flux on
a daily timescale are also captured (r2 = 0.7). In contrast,
using the area-weighted average method yielded a low (r2 = 0.14)
correlation with the EC measurements. This shows that the
footprint-weighted average method is preferable when validating
methane emission models with EC fluxes for areas with
a heterogeneous and irregular vegetation pattern. |
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