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| Titel |
Do we miss the hot spots? – The use of very high resolution aerial photographs to quantify carbon fluxes in peatlands |
| VerfasserIn |
T. Becker, L. Kutzbach, I. Forbrich, J. Schneider, D. Jager, B. Thees, M. Wilmking |
| 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 ; 5, no. 5 ; Nr. 5, no. 5 (2008-10-06), S.1387-1393 |
| Datensatznummer |
250002834
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| Publikation (Nr.) |
 copernicus.org/bg-5-1387-2008.pdf |
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| Zusammenfassung |
| Accurate determination of carbon balances in heterogeneous
ecosystems often requires the extrapolation of point based
measurements. The ground resolution (pixel size) of the extrapolation base,
e.g. a land-cover map, might thus influence the calculated carbon
balance, in particular if biogeochemical hot spots are small in size.
In this paper, we test the effects of varying ground resolution on the
calculated carbon balance of a boreal peatland consisting of
hummocks (dry), lawns (intermediate) and flarks (wet surfaces). The
generalizations in lower resolution imagery led to biased area
estimates for individual micro-site types. While areas of lawns and
hummocks were stable below a threshold resolution of
~60 cm, the maximum of the flark area was located at
resolutions below 25 cm and was then decreasing with
coarsening resolution. Using a resolution of 100 cm instead
of 6 cm led to an overestimation of total CO2 uptake of the studied peatland
area (approximately 14 600 m2) of ~5% and an underestimation of total CH4
emission of ~6%. To accurately determine the surface
area of scattered and small-sized micro-site types in heterogeneous
ecosystems (e.g. flarks in peatlands), a minimum ground resolution appears necessary. In our case this
leads to a recommended resolution of 25 cm, which can be
derived by conventional airborne imagery. The usage of high
resolution imagery from commercial satellites, e.g. Quickbird,
however, is likely to underestimate the surface area of
biogeochemical hot spots. It is important to note that the observed
resolution effect on the carbon balance estimates can be much
stronger for other ecosystems than for the investigated peatland.
In the investigated peatland the relative hot spot area of the flarks is very small and
their hot spot characteristics with respect to CH4 and CO2
fluxes is rather modest. |
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