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| Titel |
On the use of integrating FLUXNET eddy covariance and remote sensing data for model evaluation |
| VerfasserIn |
Markus Reichstein, Martin Jung, Christian Beer, Nuno Carvalhais, Enrico Tomelleri, Gitta Lasslop, Dennis Baldocchi, Dario Papale |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250037455
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| Zusammenfassung |
| The current FLUXNET database (www.fluxdata.org) of CO2, water and energy
exchange between the terrestrial biosphere and the atmosphere contains almost 1000
site-years with data from more than 250 sites, encompassing all major biomes of the
world and being processed in a standardized way (1-3). In this presentation we
show that the information in the data is sufficient to derive generalized empirical
relationships between vegetation/respective remote sensing information, climate and the
biosphere-atmosphere exchanges across global biomes. These empirical patterns are
used to generate global grids of the respective fluxes and derived properties (e.g.
radiation and water-use efficiencies or climate sensitivities in general, bowen-ratio,
AET/PET ratio). For example we revisit global “text-book” numbers such as global
Gross Primary Productivity (GPP) estimated since the 70’s as ca. 120PgC (4), or
global evapotranspiration (ET) estimated at 65km3/yr-1 (5) - for the first time with
a more solid and direct empirical basis. Evaluation against independent data at
regional to global scale (e.g. atmospheric CO2 inversions, runoff data) lends support
to the validity of our almost purely empirical up-scaling approaches. Moreover
climate factors such as radiation, temperature and water balance are identified as
driving factors for variations and trends of carbon and water fluxes, with distinctly
different sensitivities between different vegetation types. Hence, these global fields of
biosphere-atmosphere exchange and the inferred relations between climate, vegetation type
and fluxes should be used for evaluation or benchmarking of climate models or their
land-surface components, while overcoming scale-issues with classical point-to-grid-cell
comparisons.
1. M. Reichstein et al., Global Change Biology 11, 1424 (2005). 2. D. Baldocchi,
Australian Journal of Botany 56, 1 (2008). 3. D. Papale et al., Biogeosciences 3, 571
(2006). 4. D. E. Alexander, R. W. Fairbridge, Encyclopedia of Environmental Science
(Springer, Heidelberg, 1999), pp. 741. 5. T. Oki, S. Kanae, Science 313, 1068 (Aug 25,
2006) |
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