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| Titel |
BVOC ecosystem flux measurements at a high latitude wetland site |
| VerfasserIn |
T. Holst, A. Arneth, S. Hayward, A. Ekberg, M. Mastepanov, M. Jackowicz-Korczyñski, T. Friborg, P. M. Crill, K. Bäckstrand |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 4 ; Nr. 10, no. 4 (2010-02-15), S.1617-1634 |
| Datensatznummer |
250008106
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| Publikation (Nr.) |
 copernicus.org/acp-10-1617-2010.pdf |
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| Zusammenfassung |
In this study, we present summertime concentrations and fluxes of biogenic
volatile organic compounds (BVOCs) measured at a sub-arctic wetland in
northern Sweden using a disjunct eddy-covariance (DEC) technique based on a
proton transfer reaction mass spectrometer (PTR-MS). The vegetation at the
site was dominated by Sphagnum, Carex and
\textit{Eriophorum} spp. The measurements reported here cover a
period of 50 days (1 August to 19 September 2006), approximately one half of
the growing season at the site, and allowed to investigate the effect of
day-to-day variation in weather as well as of vegetation senescence on daily
BVOC fluxes, and on their temperature and light responses. The sensitivity
drift of the DEC system was assessed by comparing H3O+-ion cluster
formed with water molecules (H3O+(H2O) at m37) with water
vapour concentration measurements made using an adjacent humidity sensor,
and the applicability of the DEC method was analysed by a comparison of
sensible heat fluxes for high frequency and DEC data obtained from the sonic
anemometer. These analyses showed no significant PTR-MS sensor drift over a
period of several weeks and only a small flux-loss due to high-frequency
spectrum omissions. This loss was within the range expected from other
studies and the theoretical considerations.
Standardised (20 °C and 1000 μmol m−2 s−1 PAR) summer
isoprene emission rates found in this study of 329 μg C m−2
(ground area) h−1 were comparable with findings from
more southern boreal forests, and fen-like ecosystems. On a diel scale,
measured fluxes indicated a stronger temperature dependence than emissions
from temperate or (sub)tropical ecosystems. For the first time, to our
knowledge, we report ecosystem methanol fluxes from a sub-arctic ecosystem.
Maximum daytime emission fluxes were around 270 μg m−2 h−1
(ca. 100 μg C m−2 h−1), and during most nights small negative
fluxes directed from the atmosphere to the surface were observed. |
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