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Titel |
Fluxes and concentrations of volatile organic compounds from a South-East Asian tropical rainforest |
VerfasserIn |
B. Langford, P. K. Misztal, E. Nemitz, B. Davison, C. Helfter, T. A. M. Pugh, A. R. MacKenzie, S. F. Lim, C. N. Hewitt |
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. 17 ; Nr. 10, no. 17 (2010-09-07), S.8391-8412 |
Datensatznummer |
250008756
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Publikation (Nr.) |
copernicus.org/acp-10-8391-2010.pdf |
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Zusammenfassung |
As part of the OP3 field study of rainforest atmospheric chemistry,
above-canopy fluxes of isoprene, monoterpenes and oxygenated volatile organic
compounds were made by virtual disjunct eddy covariance from a South-East
Asian tropical rainforest in Malaysia. Approximately 500 hours of flux data
were collected over 48 days in April–May and June–July 2008. Isoprene was
the dominant non-methane hydrocarbon emitted from the forest, accounting for
80% (as carbon) of the measured emission of reactive carbon fluxes. Total
monoterpene emissions accounted for 18% of the measured reactive carbon
flux. There was no evidence for nocturnal monoterpene emissions and during
the day their flux rate was dependent on both light and temperature. The
oxygenated compounds, including methanol, acetone and acetaldehyde,
contributed less than 2% of the total measured reactive carbon flux. The
sum of the VOC fluxes measured represents a 0.4% loss of daytime
assimilated carbon by the canopy, but atmospheric chemistry box modelling
suggests that most (90%) of this reactive carbon is returned back to the
canopy by wet and dry deposition following chemical transformation. The
emission rates of isoprene and monoterpenes, normalised to
30 °C and 1000 μmol m−2 s−1 PAR,
were 1.6 mg m−2 h−1 and 0.46mg m−2 h−1
respectively, which was 4 and 1.8 times lower respectively than the default
value for tropical forests in the widely-used MEGAN model of biogenic VOC
emissions. This highlights the need for more direct canopy-scale flux
measurements of VOCs from the world's tropical forests. |
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