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| Titel |
On the relationship between ecosystem-scale hyperspectral reflectance and CO2 exchange in European mountain grasslands |
| VerfasserIn |
M. Balzarolo, L. Vescovo, A. Hammerle, D. Gianelle, D. Papale, E. Tomelleri, G. Wohlfahrt |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 10 ; Nr. 12, no. 10 (2015-05-28), S.3089-3108 |
| Datensatznummer |
250117950
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| Publikation (Nr.) |
 copernicus.org/bg-12-3089-2015.pdf |
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| Zusammenfassung |
| In this paper we explore the skill of hyperspectral reflectance measurements
and vegetation indices (VIs) derived from these in estimating carbon dioxide
(CO2) fluxes of grasslands. Hyperspectral reflectance data, CO2
fluxes and biophysical parameters were measured at three grassland sites
located in European mountain regions using standardized protocols. The
relationships between CO2 fluxes, ecophysiological variables,
traditional VIs and VIs derived using all two-band combinations of
wavelengths available from the whole hyperspectral data space were analysed.
We found that VIs derived from hyperspectral data generally explained a large
fraction of the variability in the investigated dependent variables but
differed in their ability to estimate midday and daily average CO2
fluxes and various derived ecophysiological parameters. Relationships between
VIs and CO2 fluxes and ecophysiological parameters were site-specific,
likely due to differences in soils, vegetation parameters and environmental
conditions. Chlorophyll and water-content-related VIs explained the largest
fraction of variability in most of the dependent variables. Band selection
based on a combination of a genetic algorithm with random forests (GA–rF)
confirmed that it is difficult to select a universal band region suitable
across the investigated ecosystems. Our findings have major implications for
upscaling terrestrial CO2 fluxes to larger regions and for remote- and
proximal-sensing sampling and analysis strategies and call for more
cross-site synthesis studies linking ground-based spectral reflectance with
ecosystem-scale CO2 fluxes. |
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