Details

Autor(en) / Beteiligte

• Chen, Baozhang
• Coops, Nicholas C.
• Fu, Dongjie
• Margolis, Hank A.
• Amiro, Brian D.
• Black, T. Andrew
• Arain, M. Altaf
• Barr, Alan G.
• Bourque, Charles P.-A.
• Flanagan, Lawrence B.
• Lafleur, Peter M.
• McCaughey, J. Harry
• Wofsy, Steven C.

Titel

Characterizing spatial representativeness of flux tower eddy-covariance measurements across the Canadian Carbon Program Network using remote sensing and footprint analysis

Ist Teil von

• Remote sensing of environment, 2012-09, Vol.124, p.742-755

Ort / Verlag

New York, NY: Elsevier Inc

Erscheinungsjahr

2012

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We describe a pragmatic approach for evaluating the spatial representativeness of flux tower measurements based on footprint climatology modeling analyses of land cover and remotely sensed vegetation indices. The approach was applied to the twelve flux sites of the Canadian Carbon Program (CCP) that include grassland, wetland, and temperate and boreal forests across an east–west continental gradient. The spatial variation within the footprint area was evaluated by examining the spatial structure of Normalized Difference Vegetation Index (NDVI) and land cover using geostatistical analyses of frequency distribution, variogram and window size. The results show that at most sites (i) the percentages of the target vegetation functional type (dominant land cover) observed by the CCP towers were higher than 60%; (ii) to some extent, most of the CCP sites presented anisotropically distributed patterns of NDVI in the 90% annual footprint climatology area; and (iii) the land surface heterogeneity within the flux footprint area differed among sites. Overall, the forest sites had larger fine-scale spatial variation than the grassland and wetland sites. The coniferous boreal forest sites had greater spatial variability than the two wetland sites and a coniferous temperate forest site. We conclude that the combination of footprint modeling, semivariogram and window size techniques, together with moderate spatial resolution remotely-sensed image data, is a pragmatic approach for assessing the spatial representativeness of flux tower measurements. ► We propose a method for evaluating the spatial representativeness of flux towers. ► The evaluation method includes footprint, variogram and window size analyses. ► We evaluate the representativeness of 12 Canadian Carbon Program (CCP) flux towers. ► The heterogeneity of the flux footprint area differed among CCP flux sites. ► The estimations of regional fluxes will be improved by applying this method.