 |
| Titel |
Observations of elevated formaldehyde over a forest canopy suggest missing sources from rapid oxidation of arboreal hydrocarbons |
| VerfasserIn |
W. Choi, I. C. Faloona, N. C. Bouvier-Brown, M. McKay, A. H. Goldstein, J. Mao, W. H. Brune, B. W. LaFranchi, R. C. Cohen, G. M. Wolfe, J. A. Thornton, D. M. Sonnenfroh, D. B. Millet |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 18 ; Nr. 10, no. 18 (2010-09-17), S.8761-8781 |
| Datensatznummer |
250008778
|
| Publikation (Nr.) |
 copernicus.org/acp-10-8761-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| To better understand the processing of biogenic VOCs (BVOCs) in the pine
forests of the US Sierra Nevada, we measured HCHO at Blodgett Research
Station using Quantum Cascade Laser Spectroscopy (QCLS) during the Biosphere
Effects on Aerosols and Photochemistry Experiment (BEARPEX) of late summer
2007. Four days of the experiment exhibited particularly copious HCHO, with
midday peaks between 15–20 ppbv, while the other days developed delayed
maxima between 8–14 ppbv in the early evening. From the expansive
photochemical data set, we attempt to explain the observed HCHO
concentrations by quantifying the various known photochemical production and
loss terms in its chemical budget. Overall, known chemistry predicts a
factor of 3–5 times less HCHO than observed. By examining diurnal patterns
of the various budget terms we conclude that, during the high HCHO period,
local, highly reactive oxidation chemistry produces an abundance of
formaldehyde at the site. The results support the hypothesis of previous
work at Blodgett Forest suggesting that large quantities of oxidation
products, observed directly above the ponderosa pine canopy, are evidence of
profuse emissions of very reactive volatile organic compounds (VR-VOCs) from
the forest. However, on the majority of days, under generally cooler and
more moist conditions, lower levels of HCHO develop primarily influenced by
the influx of precursors transported into the region along with the
Sacramento plume. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|