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| Titel |
Testing the applicability of neural networks as a gap-filling method using CH4 flux data from high latitude wetlands |
| VerfasserIn |
S. Dengel, D. Zona, T. Sachs, M. Aurela, M. Jammet, F. J. W. Parmentier, W. Oechel, T. Vesala |
| 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 ; 10, no. 12 ; Nr. 10, no. 12 (2013-12-11), S.8185-8200 |
| Datensatznummer |
250085474
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| Publikation (Nr.) |
 copernicus.org/bg-10-8185-2013.pdf |
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| Zusammenfassung |
Since the advancement in CH4 gas analyser technology and its
applicability to eddy covariance flux measurements, monitoring of CH4
emissions is becoming more widespread. In order to accurately determine the
greenhouse gas balance, high quality gap-free data is required. Currently
there is still no consensus on CH4 gap-filling methods, and methods
applied are still study-dependent and often carried out on low resolution,
daily data.
In the current study, we applied artificial neural networks to six
distinctively different CH4 time series from high latitudes, explain
the method and test its functionality. We discuss the applicability of
neural networks in CH4 flux studies, the advantages and disadvantages
of this method, and what information we were able to extract from such
models.
Three different approaches were tested by including drivers such as air and
soil temperature, barometric air pressure, solar radiation, wind direction
(indicator of source location) and in addition the lagged effect of water
table depth and precipitation. In keeping with the principle of parsimony,
we included up to five of these variables traditionally measured at CH4
flux measurement sites. Fuzzy sets were included representing the seasonal
change and time of day. High Pearson correlation coefficients (r) of up to
0.97 achieved in the final analysis are indicative for the high performance
of neural networks and their applicability as a gap-filling method for
CH4 flux data time series. This novel approach which we show to be
appropriate for CH4 fluxes is a step towards standardising CH4
gap-filling protocols. |
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