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Titel |
Analysis of remotely-sensed global canopy scale fluorescence as a predictor for GPP |
VerfasserIn |
Maximilian Voigt, Luis Guanter, Martin Jung |
Konferenz |
EGU General Assembly 2013
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 15 (2013) |
Datensatznummer |
250073818
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Zusammenfassung |
The uncertainties of modeling terrestrial global gross primary productivity (GPP) are large,
partly because of a lack of direct global measurements. GPP is the amount of atmospheric
carbon dioxide taken up by ecosystems via photosynthesis, which is the single largest flux of
the global land carbon budget and makes plants an important component of the global climate
system. The measurement of fluorescence, which is linked to photosynthesis therefore could
be of vital importance for the modeling of GPP. An adequate technique to monitor the
fluorescence signal on a global scale, whose maximum lies in a spectral region of 650Â nm –
800Â nm, is satellite remote sensing. This was made possible by the satellite mission
GOSAT, which was launched in January 2009 and is able to measure the signal
globally with a relatively fine spatial resolution (~ 10Â km) and at narrow spectral
windows around 770Â nm and 759Â nm. Although the link between photosynthesis and
fluorescence at the leaf scale is, based on lab– and field–based experiments, relatively well
known, the relationship at the canopy level and for the coarse spatial resolutions
provided by space–borne instruments (of the order of 10Â km – 100Â km) is still
uninvestigated.
The objective of this study is to explore the relationship between the retrieved
fluorescence signal from GOSAT on global scale with several well investigated
vegetation indices, like FAPAR and EVI, as well as meteorological parameters such as
incoming radiation, soil water content or temperature potentially driving photosynthesis
down-regulation. The final goal is to assess the information content of all these parameters for
the statistical modelling of GPP. Fluorescence is expected to have a higher information
content than the latter mentioned indices in situations where the leaves are still green, but the
environmental conditions are limiting the productivity of the plants, because of its linkage to
ecosystem phenology. |
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