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Testing the applicability of neural networks as a gap-filling method using CH4 flux data from high latitude wetlands

Dengel, S. ; Zona, D. ; Sachs, T. ; Aurela, M. ; Jammet, M. ; Parmentier, Frans-Jan LU ; Oechel, W. and Vesala, T. (2013) In Biogeosciences 10. p.8185-8200
Abstract
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,... (More)
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. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biogeosciences
volume
10
pages
8185 - 8200
publisher
Copernicus Publications
external identifiers
  • wos:000329054600025
  • scopus:84890494740
ISSN
1726-4189
DOI
10.5194/bg-10-8185-2013
language
English
LU publication?
yes
id
22dd0053-ee59-4857-8c9f-9fcc6be0e71b (old id 4221437)
date added to LUP
2016-04-01 10:11:42
date last changed
2020-07-29 01:25:02
@article{22dd0053-ee59-4857-8c9f-9fcc6be0e71b,
  abstract     = {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. <br/><br>
<br/><br>
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. <br/><br>
<br/><br>
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.},
  author       = {Dengel, S. and Zona, D. and Sachs, T. and Aurela, M. and Jammet, M. and Parmentier, Frans-Jan and Oechel, W. and Vesala, T.},
  issn         = {1726-4189},
  language     = {eng},
  pages        = {8185--8200},
  publisher    = {Copernicus Publications},
  series       = {Biogeosciences},
  title        = {Testing the applicability of neural networks as a gap-filling method using CH4 flux data from high latitude wetlands},
  url          = {http://dx.doi.org/10.5194/bg-10-8185-2013},
  doi          = {10.5194/bg-10-8185-2013},
  volume       = {10},
  year         = {2013},
}