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| Titel |
Characterisation of bioaerosol emissions from a Colorado pine forest: results from the BEACHON-RoMBAS experiment |
| VerfasserIn |
I. Crawford, N. H. Robinson, M. J. Flynn, V. E. Foot, M. W. Gallagher, J. A. Huffman, W. R. Stanley, P. H. Kaye |
| 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 ; 14, no. 16 ; Nr. 14, no. 16 (2014-08-25), S.8559-8578 |
| Datensatznummer |
250118971
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| Publikation (Nr.) |
 copernicus.org/acp-14-8559-2014.pdf |
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| Zusammenfassung |
The behaviour of primary biological aerosols (PBAs) at an elevated,
un-polluted North American forest site was studied using an ultra
violet-light induced fluorescence (UV-LIF) measurement technique in
conjunction with hierarchical agglomerative cluster analysis
(HA-CA). Contemporaneous UV-LIF measurements were made with two
wide-band integrated bioaerosol spectrometers, WIBS-3 and WIBS-4,
which sampled close to the forest floor and via a continuous
vertical profiling system, respectively. Additionally,
meteorological parameters were recorded at various heights
throughout the forest and used to estimate PBAP (Primary Biological Aerosol Particle) fluxes. HA-CA using
data from the two, physically separated WIBS instruments
independently yielded very similar cluster solutions.
All fluorescent clusters displayed a diurnal minimum at midday at
the forest floor with maximum concentration occurring at night.
Additionally, the number concentration of each fluorescent cluster
was enhanced, to different degrees, during wet periods. A cluster
that displayed the greatest enhancement and highest concentration
during sustained wet periods appears consistent with behaviour
reported for fungal spores. A cluster that appears to be
behaviourally consistent with bacteria dominated during dry
periods. Fluorescent particle concentrations were found to be
greater within the forest canopy than at the forest floor,
indicating that the canopy was the main source of these particles
rather than the minimal surface vegetation, which appeared to
contribute little to overall PBA concentrations at this site.
Fluorescent particle concentration was positively correlated with
relative humidity (RH), and parameterisations of the aerosol
response during dry and wet periods are reported. The
aforementioned fungal spore-like cluster displayed a strong positive
response to increasing RH. The bacteria-like cluster responded more
strongly to direct rain-fall events than other PBA types. Peak
concentrations of this cluster are shown to be linearly
correlated to the log of peak rainfall rates.
Parallel studies by Huffman et al. (2013) and Prenni et al. (2013) showed
that the fluorescent particle concentrations correlated linearly
with ice nuclei (IN) concentrations at this site during rain events.
We discuss this result in conjunction with our cluster analysis to
appraise the candidate IN. |
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