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Measurements of reactive nitrogen oxides (NO/y/) within and above a tropical forest canopy in the wet seasonMeasurements of ambient concentrations of reactive nitrogen oxides were made in the Amazon rain forest, near Manaus, Brazil, continuously at 39 m (above the canopy), and on several days and nights at 19 m (within the canopy). Concentrations were very low, typically 100-700 pptv, except for brief periods when up to 5000 pptv of NO(y) was observed, indicating polluted air from the urban area of Manaus. The forest was a net sink for NO(y) with the NO(y) flux = -7.6 + or - 5.0) x 10 to the 9th molecules/sq cm per sec in unpolluted periods, even though soils emitted NO at a significant rate (8.9 + or - 1.5 x 10 to the 9th molecules/sq cm per sec). The deposition rate for NO(y) appeared to be much larger during the daytime than at night, suggesting that uptake was controlled either by plant processes (stomatal opening) or by supply of reactive components of NO(y) (e.g., HNO3) during the daytime. Implications for regional and global atmospheric chemistry are discussed.
Document ID
19900065050
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Bakwin, Peter S.
(Harvard Univ. Cambridge, MA, United States)
Wofsy, Steven C.
(Harvard Univ. Cambridge, MA, United States)
Fan, Song-Miao
(Harvard University Cambridge, MA, United States)
Date Acquired
August 14, 2013
Publication Date
September 20, 1990
Publication Information
Publication: Journal of Geophysical Research
Volume: 95
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
90A52105
Funding Number(s)
CONTRACT_GRANT: NAG1-55
CONTRACT_GRANT: NSF ATM-84-13153
Distribution Limits
Public
Copyright
Other

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