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          Institute: MPI für Chemie     Collection: Publikationen MPI für Chemie     Display Documents

ID: 18252.0, MPI für Chemie / Publikationen MPI für Chemie
Eddy covariance measurements of nitric oxide flux within an Amazonian rain forest
Authors:Rummel, U.; Ammann, C.; Gut, A.; Meixner, F. X.; Andreae, M. O.
Date of Publication (YYYY-MM-DD):2002-09
Title of Journal:Journal of Geophysical Research
Journal Abbrev.:J. Geophys. Res.
Issue / Number:D20
Sequence Number of Article:8050
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:NO flux measurements by the eddy covariance technique were performed within a tropical rain forest 1 m and 11 m above the forest floor. A fast-response chemiluminescence NO analyzer with a sampling tube of 25 m length was used for the gas measurements. Nighttime similarity between the cospectra of sensible heat and the NO flux offered the possibility to quantify the high-frequency attenuation of the NO eddy covariance by spectral analysis. Integrated flux correction factors of about 21% for the system at 1 m and 5% for the one at 11 m above ground were calculated by transfer functions adopted from the literature and confirmed experimentally. For an independent validation the results of the eddy covariance system were compared with the NO soil emissions obtained by dynamic chambers. For nighttime averages, good agreement within 10% was found. The obtained NO fluxes were 3.5 +/- 0.14 and 4.8 +/- 0.39 ng N m(-2) s(-1) for the two investigated periods at 1 and 11 m heights, respectively. During the day, chemical reaction with ozone entrained from aloft reduced the fraction of the soil-emitted NO that reached the measuring height of the eddy covariance system. The average flux showed a reduction of 48% at 1 m and 92% at 11 m height compared to the corresponding soil emission measured by the chamber system.
Free Keywords:eddy covariance; nitric oxide flux; turbulence; Amazonian rain forest; cospectral similarity
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Chemie/Biogeochemie
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