Frans-Jan Parmentier
Docent
Evaluation of a plot-scale methane emission model using eddy covariance observations and footprint modelling
Författare
Summary, in English
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 (r(2) = 0.7). In contrast, using the area-weighted average method yielded a low (r(2) = 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.
Avdelning/ar
- Institutionen för naturgeografi och ekosystemvetenskap
Publiceringsår
2014
Språk
Engelska
Sidor
4651-4664
Publikation/Tidskrift/Serie
Biogeosciences
Volym
11
Issue
17
Dokumenttyp
Artikel i tidskrift
Förlag
Copernicus GmbH
Ämne
- Physical Geography
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1726-4189