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Titel |
Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically resolved aerosol fluxes |
VerfasserIn |
D. K. Farmer, J. R. Kimmel, G. Phillips, K. S. Docherty, D. R. Worsnop, D. Sueper, E. Nemitz, J. L. Jimenez |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1867-1381
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Measurement Techniques ; 4, no. 6 ; Nr. 4, no. 6 (2011-06-29), S.1275-1289 |
Datensatznummer |
250002022
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Publikation (Nr.) |
copernicus.org/amt-4-1275-2011.pdf |
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Zusammenfassung |
Although laboratory studies show that biogenic volatile organic compounds
(VOCs) yield substantial secondary organic aerosol (SOA), production of
biogenic SOA as indicated by upward fluxes has not been conclusively
observed over forests. Further, while aerosols are known to deposit to
surfaces, few techniques exist to provide chemically-resolved particle
deposition fluxes. To better constrain aerosol sources and sinks, we have
developed a new technique to directly measure fluxes of chemically-resolved
submicron aerosols using the high-resolution time-of-flight aerosol mass
spectrometer (HR-AMS) in a new, fast eddy covariance mode. This approach
takes advantage of the instrument's ability to quantitatively identify both
organic and inorganic components, including ammonium, sulphate and nitrate,
at a temporal resolution of several Hz. The new approach has been
successfully deployed over a temperate ponderosa pine plantation in
California during the BEARPEX-2007 campaign, providing both total and
chemically resolved non-refractory (NR) PM1 fluxes. Average deposition
velocities for total NR-PM1 aerosol at noon were 2.05 ± 0.04 mm s−1.
Using a high resolution measurement of the NH2+ and NH3+
fragments, we demonstrate the first eddy covariance flux measurements of
particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm s−1 and are dominated by deposition of ammonium sulphate. |
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