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| Titel |
Complex night-time CO2 fluxes at Norunda site |
| VerfasserIn |
Meelis Mölder, Anders Lindroth |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250150925
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| Publikation (Nr.) |
 EGU/EGU2017-15451.pdf |
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| Zusammenfassung |
| Flux measurement at Norunda, Sweden have been carried out since the summer of 1994. In 2007, the old Gill R2 and LI-6262 were replaced by a Metek USA-1 sonic and a LI-7000 gas analyser. This system is in operation even today. The Norunda site is characterized by a flat landscape and a 26 m tall, more than 100-years-old pine-spruce forest nearest the tower. On annual bases the site has shown to be a source of CO2, mainly because of high night-time fluxes. Night-time CO2 fluxes are not only high, they also very variable. Night-time fluxes are usually claimed to be underestimated because of decoupling between the under-story and the above-canopy air. Besides this underestimation many night-time flux values in Norunda seem to be overestimated. Those values could go up to 50 µmol m-1 s-1. The standard ustar-filtering might not be a proper method for the analysis. We will look for alternative filtering methods and show the sensitivity of annual CO2 budgets on the used methods. |
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