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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys. Discuss., 11, 29251-29282, 2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
28 Oct 2011
Review status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). A final paper in ACP is not foreseen.
The Morning NO x maximum in the forest atmosphere boundary layer
M. Alaghmand1, P. B. Shepson1,2,3, T. K. Starn4, B. T. Jobson5, H. W. Wallace5, M. A. Carroll6, S. B. Bertman7, B. Lamb5, S. L. Edburg5, X. Zhou8, E. Apel9, D. Riemer10, P. Stevens11, and F. Keutsch12
1Purdue University, Dept. of Chemistry, West Lafayette, IN, USA
2Dept. of Earth and Atmospheric Sciences, West Lafayette, IN, USA
3Purdue Climate Change Research Center, West Lafayette, IN, USA
4West Chester University, Dept. of Chemistry, West Chester, PA, USA
5Washington State University, Dept. of Civil and Environmental Engineering, Pullman, WA, USA
6University of Michigan, Dept. of Atmospheric, Oceanic, and Space Sciences, Ann Arbor, MI, USA
7Western Michigan University, Dept. of Chemistry, Kalamazoo, MI, USA
8Wadsworth Center, SUNY-Albany, NY, USA
9National Center for Atmospheric Research, Boulder, CO, USA
10RSMAS, University of Miami, Miami, FL, USA
11Indiana University, School of Public and Environmental Affairs, Bloomington, IN, USA
12University of Wisconsin, Madison, Dept. of Chemistry, Madison, WI, USA

Abstract. During the 1998, 2000, 2001, 2008, and 2009 summer intensives of the Program for Research on Oxidants: PHotochemistry, Emissions and Transport (PROPHET), ambient measurement of nitrogen oxides (NO + NO2 = NOx) were conducted. NO and NOx mole fractions displayed a diurnal pattern with NOx frequently highest in early morning. This pattern has often been observed in other rural areas. In this paper, we discuss the potential sources and contributing factors of the frequently observed morning pulse of NOx. Of the possible potential contributing factors to the observed morning pulse of NO and NOx, we find that surface-layer transport and slow upward mixing from soil emissions, related to the thermodynamic stability in the nocturnal boundary layer (NBL) before its morning breakup are the largest contributors. The morning NOx peak can significantly impact boundary layer chemistry, e.g. through production of HONO on surfaces, and by increasing the importance of NO3 chemistry in the morning boundary layer.

Citation: Alaghmand, M., Shepson, P. B., Starn, T. K., Jobson, B. T., Wallace, H. W., Carroll, M. A., Bertman, S. B., Lamb, B., Edburg, S. L., Zhou, X., Apel, E., Riemer, D., Stevens, P., and Keutsch, F.: The Morning NO x maximum in the forest atmosphere boundary layer, Atmos. Chem. Phys. Discuss., 11, 29251-29282, doi:10.5194/acpd-11-29251-2011, 2011.
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