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Reactive nitrogen oxides and ozone above a taiga woodlandMeasurements of reactive nitrogen oxides (NO(x) and NO(y)) and ozone (O3) were made in the planetary boundary layer (PBL) above a taiga woodland in northern Quebec, Canada, during June-August, 1990, as part of NASA Artic Boundary Layer Expedition (ABLE) 3B. Levels of nitrogen oxides and O3 were strongly modulated by the synoptic scale meteorology that brought air from various source regions to the site. Industrial pollution from the Great Lakes region of the U.S. and Canada appears to be a major source for periodic elevation of NO(x), and NO(y) and O3. We find that NO/NO2 ratios at this site at midday were approximately 50% those expected from a simple photochemical steady state between NO(x) and O3, in contrast to our earlier results from the ABLE 3A tundra site. The difference between the taiga and tundra sites is likely due to much larger emissions of biogenic hydrocarbons (particularly isoprene) from the taiga vegetation. Hydrocarbon photooxidation leads to relatively rapid production of peroxy radicals, which convert NO to NO2, at the taiga site. Ratios of NO(x) to NO(y) were typically 2-3 times higher in the PBL during ABLE 3B than during ABLE 3A. This is probably the result of high PAN levels and suppressed formation of HNO3 from NO2 due to high levels of biogenic hydrocarbons at the ABLE 3B site.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Bakwin, Peter S. (Harvard Univ. Cambridge, MA, United States)
Jacob, Daniel J. (Harvard Univ. Cambridge, MA, United States)
Wofsy, Steven C. (Harvard Univ. Cambridge, MA, United States)
Munger, J. William (Harvard Univ. Cambridge, MA, United States)
Daube, Bruce C. (Harvard Univ. Cambridge, MA, United States)
Bradshaw, John D. (Georgia Institute of Technology, Atlanta, GA United States)
Sandholm, Scott T. (Georgia Institute of Technology, Atlanta, GA United States)
Talbot, Robert W. (Univ. of New Hampshire, Durham, NH United States)
Singh, Hanwant B. (NASA Ames Research Center Moffett Field, CA, United States)
Gregory, Gerald L. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 16, 2013
Publication Date
January 20, 1994
Publication Information
Publication: Journal of Geophysical Research
Volume: 99
Issue: D1
ISSN: 0148-0227
Subject Category
Funding Number(s)
Distribution Limits