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| Titel |
Measurements of OVOC fluxes by eddy covariance using a proton-transfer-reaction mass spectrometer – method development at a coastal site |
| VerfasserIn |
M. Yang, R. Beale, T. Smyth, B. Blomquist |
| 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 ; 13, no. 13 ; Nr. 13, no. 13 (2013-07-01), S.6165-6184 |
| Datensatznummer |
250018727
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| Publikation (Nr.) |
 copernicus.org/acp-13-6165-2013.pdf |
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| Zusammenfassung |
| We present here vertical fluxes of oxygenated volatile
organic compounds (OVOCs) measured with eddy covariance (EC) during the period of March to
July 2012 near the southwest coast of the United Kingdom. The performance of
the proton-transfer-reaction mass spectrometer (PTR-MS) for flux measurement
is characterized, with additional considerations given to the homogeneity
and stationarity assumptions required by EC. Observed mixing ratios and
fluxes of OVOCs (specifically methanol, acetaldehyde, and acetone) vary
significantly with time of day and wind direction. Higher mixing ratios and
fluxes of acetaldehyde and acetone are found in the daytime and from the
direction of a forested park, most likely due to light-driven emissions from
terrestrial plants. Methanol mixing ratio and flux do not demonstrate
consistent diel variability, suggesting sources in addition to plants. We
estimate air–sea exchange and photochemical rates of these compounds, which
are compared to measured vertical fluxes. For acetaldehyde, the mean (1σ)
mixing ratio of 0.13 (0.02) ppb at night may be maintained by
oceanic emission, while photochemical destruction outpaces production during
the day. Air–sea exchange and photochemistry are probably net sinks of
methanol and acetone in this region. Their nighttime mixing ratios of 0.46
(0.20) and 0.39 (0.08) ppb appear to be affected more by terrestrial
emissions and long-distance transport, respectively. |
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