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| Titel |
Forest canopy interactions with nucleation mode particles |
| VerfasserIn |
S. C. Pryor, K. E. Hornsby, K. A. Novick |
| 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. 21 ; Nr. 14, no. 21 (2014-11-14), S.11985-11996 |
| Datensatznummer |
250119160
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| Publikation (Nr.) |
 copernicus.org/acp-14-11985-2014.pdf |
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| Zusammenfassung |
| Ultrafine particle size distributions through a deciduous forest canopy
indicate that nucleation mode particle concentrations decline with depth
into the canopy, such that number concentrations at the bottom of the canopy
are an average of 16% lower than those at the top. However, growth rates
of nucleation mode particles (diameters 6–30 nm) are invariant with height
within the canopy, which implies that the semi-volatile gases contributing
to their growth are comparatively well-mixed through the canopy. Growth
rates of nucleation mode particles during a meteorological drought year
(2012) were substantially lower than during a meteorologically normal year
with high soil water potential (2013). This may reflect suppression of
actual biogenic volatile organic compound (BVOC) emissions by drought and thus a reduction in the production of
condensable products during the drought-affected vegetation season. This
hypothesis is supported by evidence that growth rates during the normal year
exhibit a positive correlation with emissions of BVOC modeled on observed forest composition, leaf area
index, temperature and photosynthetically active radiation (PAR), but particle growth rates during the
drought-affected vegetation season are not correlated with modeled BVOC
emissions. These data thus provide indirect evidence that drought stress in
forests may reduce BVOC emissions and limit growth of nucleation mode
particles to climate-relevant sizes. |
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