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Lake Maggiore - Italy, 3-6 April 2000

Estimation of Net Primary and Net Ecosystem Productivity of European terrestrial ecosystems by means of the C-Fix model and NOAA/AVHRR data.

Frank Veroustraete and Hendrik Sabbe
Flemish Institute for Technological Research (Vito)
Centre for Remote Sensing and Atmospheric Processes (TAP)

Paper (pdf file, 559 k)

In recent years, a suite of primary productivity models has been developed, to address issues related to food security and biotic responses to climatic warming. Traditional approaches to assess primary productivity range from empirical climate correlation models to mechanistic ecophysiological models. These approaches all operate on point measurements that are extrapolated in space and time. Since landscapes are quite heterogeneous, the spatial scaling (upscaling) of point measurements is problematic, relative to the sampling density. Diagnostic or inverse (top-down) approaches to primary production like C-Fix have received a great deal of attention in recent years, owing to their avoidance of spatial extrapolation or land-cover classification, and the unique use made of remotely sensed observational data. The family of models to which C-Fix belongs to are genuinely called PEM’s (Production Efficiency Models). This means that C-Fix inherently is spatially explicit, relying on observations that are specific for a given time and location, and hence the model is driven by satellite observations.

C-Fix is a tool to create geo-referenced NPP (Net Primary Productivity) data layers for use in durable development planning and decision-making processes (Kyoto protocol). State-of-the-art algorithms describing carbon uptake and release mechanisms of carbon dioxide from vegetation cover in relation to meteorological conditions and satellite based quantification of the fraction of absorbed photosynthetically active radiation (fAPAR), allow for the build-up of yearly, geo-referenced datasets of NPP and NEP. Specific regions of interest (ROI’s) can be specified for use in GIS and land management planning environments.

In the work presented here, the modelling concepts of C-Fix will be discussed. The NOAA/AVHRR pre-processing steps to derive a pan- European fAPAR data set will be discussed. C-Fix NEP pixel simulations will be compared with data obtained from the EUROFLUX carbon exchange measurement sites. Hence the plausibility of the approach to determine NEP will be demonstrated. Finally a pan-European carbon budget will be presented and discussed within the framework of results obtained during the EUROFLUX project.