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Titel |
Using MODIS derived fPAR with ground based flux tower measurements to derive the light use efficiency for two Canadian peatlands |
VerfasserIn |
J. Connolly, N. T. Roulet, J. W. Seaquist, N. M. Holden, P. M. Lafleur, E. R. Humphreys, B. W. Heumann, S. M. Ward |
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 ; 6, no. 2 ; Nr. 6, no. 2 (2009-02-19), S.225-234 |
Datensatznummer |
250003432
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Publikation (Nr.) |
copernicus.org/bg-6-225-2009.pdf |
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Zusammenfassung |
We used satellite remote sensing data; fraction of photosynthetically active
radiation absorbed by vegetation (fPAR) from the Moderate Resolution Imaging
Spectroradiometer (MODIS) in combination with tower eddy covariance and
meteorological measurements to characterise the Light Use Efficiency
parameter (ε) variability and the maximum ε
(εmax) for two contrasting Canadian peatlands. Eight-day
MODIS fPAR data were acquired for the Mer Bleue (2000 to 2003) and Western
Peatland (2004). Flux tower eddy covariance and meteorological measurements
were integrated to the same eight-day time stamps as the MODIS fPAR data. A
light use efficiency model: GPP = ε×APAR (where GPP is Gross
Primary Productivity and APAR is absorbed photosynthetically active
radiation) was used to calculate ε. The εmax
value for each year (2000 to 2003) at the Mer Bleue bog ranged from
0.58 g C MJ−1 to 0.78 g C MJ−1 and was 0.91 g C MJ−1 in 2004, for the
Western Peatland. The average growing season ε for the Mer
Bleue bog for the four year period was 0.35 g C MJ−1 and for the
Western Peatland in 2004 was 0.57 g C MJ−1. The average snow free
period for the Mer Bleue bog over the four years was 0.27 g C MJ−1 and
for the Western Peatland in 2004 was 0.39 g C MJ−1. Using the light use
efficiency method we calculated the εmax and the annual
variability in ε for two Canadian peatlands. We determined that
temperature was a growth-limiting factor at both sites Vapour Pressure
Deficit (VPD) however was not. MODIS fPAR is a useful tool for the
characterization of ε at flux tower sites. |
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