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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 112,
D12S05,
doi:10.1029/2006JD007912,
2007
Surface and lightning sources of nitrogen oxides over the United States: Magnitudes, chemical evolution, and outflow
R. C. Hudman
Department of Earth and Planetary Sciences and Division of Engineering and Applied Sciences, Harvard University, Cambridge,
Massachusetts, USA
D. J. Jacob
Department of Earth and Planetary Sciences and Division of Engineering and Applied Sciences, Harvard University, Cambridge,
Massachusetts, USA
S. Turquety
Department of Earth and Planetary Sciences and Division of Engineering and Applied Sciences, Harvard University, Cambridge,
Massachusetts, USA
E. M. Leibensperger
Department of Earth and Planetary Sciences and Division of Engineering and Applied Sciences, Harvard University, Cambridge,
Massachusetts, USA
L. T. Murray
Department of Earth and Planetary Sciences and Division of Engineering and Applied Sciences, Harvard University, Cambridge,
Massachusetts, USA
S. Wu
Department of Earth and Planetary Sciences and Division of Engineering and Applied Sciences, Harvard University, Cambridge,
Massachusetts, USA
A. B. Gilliland
Air Resources Laboratory, Atmospheric Sciences Modeling Division, NOAA, U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, USA
M. Avery
Atmospheric Sciences Division, NASA Langley Research Center, Hampton, Virginia, USA
T. H. Bertram
College of Chemistry, University of California, Berkeley, California, USA
W. Brune
Department of Meteorology, Pennsylvania State University, University Park, Pennsylvania, USA
R. C. Cohen
College of Chemistry, University of California, Berkeley, California, USA
J. E. Dibb
Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire, USA
F. M. Flocke
Earth Observing Laboratory, National Center for Atmospheric Research, Boulder, Colorado, USA
A. Fried
Earth Observing Laboratory, National Center for Atmospheric Research, Boulder, Colorado, USA
J. Holloway
Cooperative Institute for Research In Environmental Science, University of Colorado, Boulder, Colorado, USA Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
J. A. Neuman
Cooperative Institute for Research In Environmental Science, University of Colorado, Boulder, Colorado, USA Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
R. Orville
Department of Atmospheric Science, Texas A&M University, College Station, Texas, USA
A. Perring
College of Chemistry, University of California, Berkeley, California, USA
X. Ren
Department of Meteorology, Pennsylvania State University, University Park, Pennsylvania, USA
G. W. Sachse
Atmospheric Sciences Division, NASA Langley Research Center, Hampton, Virginia, USA
H. B. Singh
NASA Ames Research Center, Moffett Field, California, USA
A. Swanson
Earth Observing Laboratory, National Center for Atmospheric Research, Boulder, Colorado, USA Cooperative Institute for Research In Environmental Science, University of Colorado, Boulder, Colorado, USA Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
P. J. Wooldridge
College of Chemistry, University of California, Berkeley, California, USA
Abstract
We use observations from two aircraft during the ICARTT campaign over the eastern United States and North Atlantic during
summer 2004, interpreted with a global 3-D model of tropospheric chemistry (GEOS-Chem) to test current understanding of regional
sources, chemical evolution, and export of NOx. The boundary layer NOx data provide top-down verification of a 50% decrease in power plant and industry NOx emissions over the eastern United States between 1999 and 2004. Observed NOx concentrations at 8–12 km altitude were 0.55 ± 0.36 ppbv, much larger than in previous U.S. aircraft campaigns (ELCHEM, SUCCESS,
SONEX) though consistent with data from the NOXAR program aboard commercial aircraft. We show that regional lightning is the
dominant source of this upper tropospheric NOx and increases upper tropospheric ozone by 10 ppbv. Simulating ICARTT upper tropospheric NOx observations with GEOS-Chem requires a factor of 4 increase in modeled NOx yield per flash (to 500 mol/flash). Observed OH concentrations were a factor of 2 lower than can be explained from current
photochemical models, for reasons that are unclear. A NOy-CO correlation analysis of the fraction f of North American NOx emissions vented to the free troposphere as NOy (sum of NOx and its oxidation products) shows observed f = 16 ± 10% and modeled f = 14 ± 9%, consistent with previous studies. Export to the lower free troposphere is mostly HNO3 but at higher altitudes is mostly PAN. The model successfully simulates NOy export efficiency and speciation, supporting previous model estimates of a large U.S. anthropogenic contribution to global
tropospheric ozone through PAN export.
Received 11
August
2006;
accepted 5
January
2007;
published 18
April
2007.
Keywords: reactive nitrogen;
pollution;
lightning.
Index Terms: 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0345 Atmospheric Composition and Structure: Pollution: urban and regional (0305, 0478, 4251); 0368 Atmospheric Composition and Structure: Troposphere: constituent transport and chemistry; 3324 Atmospheric Processes: Lightning; 9350 Geographic Location: North America.
Read Full Article (file size: 2098323 bytes) Cited by
Citation: Hudman, R. C., et al.
(2007),
Surface and lightning sources of nitrogen oxides over the United States: Magnitudes, chemical evolution, and outflow,
J. Geophys. Res.,
112,
D12S05,
doi:10.1029/2006JD007912.
Copyright 2007 by the American Geophysical Union.
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