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| Titel |
Net ecosystem exchange of carbon dioxide and water of far eastern Siberian Larch (Larix cajanderii) on permafrost |
| VerfasserIn |
A. J. Dolman, T. C. Maximov, E. J. Moors, A. P. Maximov, J. A. Elbers, A. V. Kononov, M. J. Waterloo, M. K. Molen |
| 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 ; 1, no. 2 ; Nr. 1, no. 2 (2004-12-23), S.133-146 |
| Datensatznummer |
250000138
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| Publikation (Nr.) |
 copernicus.org/bg-1-133-2004.pdf |
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| Zusammenfassung |
| Observations of the net ecosystem exchange of water and CO2 were made
during two seasons in 2000 and 2001 above a Larch forest in Far East Siberia
(Yakutsk). The measurements were obtained by eddy correlation. There is a
very sharply pronounced growing season of 100 days when the forest is
leaved. Maximum half hourly uptake rates are 18 µmol m-2 s-1;
maximum respiration rates are 5 µmol m-2 s-1. Net annual
sequestration of carbon was estimated at 160 gCm-2 in 2001.
Applying no correction for low friction velocities added 60 g C m-2.
The net carbon exchange of the forest was extremely sensitive to
small changes in weather that may switch the forest easily from a sink to a
source, even in summer. June was the month with highest uptake in 2001.
The average evaporation rate of the forest approached 1.46 mm day-1
during the growing season, with peak values of 3 mm day-1 with an
estimated annual evaporation of 213 mm, closely approaching the average
annual rainfall amount. 2001 was a drier year than 2000 and this is
reflected in lower evaporation rates in 2001 than in 2000.
The surface conductance of the forest shows a marked response to increasing
atmospheric humidity deficits. This affects the CO2 uptake and
evaporation in a different manner, with the CO2 uptake being more
affected. There appears to be no change in the relation between surface
conductance and net ecosystem uptake normalized by the atmospheric humidity
deficit at the monthly time scale. The response to atmospheric humidity
deficit is an efficient mechanism to prevent severe water loss during the
short intense growing season. The associated cost to the sequestration of
carbon may be another explanation for the slow growth of these forests in
this environment. |
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