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Spatial extrapolation of light use efficiency model parameters to predict gross primary production

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Author(s): Judith Elisabeth Horn | Karsten Schulz

Journal: Journal of Advances in Modeling Earth Systems
ISSN 1942-2466

Volume: 3;
Issue: 12;
Start page: M12001;
Date: 2011;
Original page

Keywords: VAT | land surface processes | biogeochemical cycles | gross primary production | carbon uptake | light use efficiency model | model parameters | extrapolation | regionalization | support vector regression | FLUXNET.

ABSTRACT
To capture the spatial and temporal variability of the gross primary production as a key component of the global carbon cycle, the light use efficiency modeling approach in combination with remote sensing data has shown to be well suited. Typically, the model parameters, such as the maximum light use efficiency, are either set to a universal constant or to land class dependent values stored in look-up tables. In this study, we employ the machine learning technique support vector regression to explicitly relate the model parameters of a light use efficiency model calibrated at several FLUXNET sites to site-specific characteristics obtained by meteorological measurements, ecological estimations and remote sensing data. A feature selection algorithm extracts the relevant site characteristics in a cross-validation, and leads to an individual set of characteristic attributes for each parameter. With this set of attributes, the model parameters can be estimated at sites where a parameter calibration is not possible due to the absence of eddy covariance flux measurement data. This will finally allow a spatially continuous model application. The performance of the spatial extrapolation scheme is evaluated with a cross-validation approach, which shows the methodology to be well suited to recapture the variability of gross primary production across the study sites.

Tango Jona
Tangokurs Rapperswil-Jona

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