Articles | Volume 15, issue 9
Atmos. Chem. Phys., 15, 5161–5179, 2015
https://doi.org/10.5194/acp-15-5161-2015
Atmos. Chem. Phys., 15, 5161–5179, 2015
https://doi.org/10.5194/acp-15-5161-2015

Research article 11 May 2015

Research article | 11 May 2015

Origin of springtime ozone enhancements in the lower troposphere over Beijing: in situ measurements and model analysis

J. Huang1,*, H. Liu1, J. H. Crawford2, C. Chan3, D. B. Considine3,4, Y. Zhang5, X. Zheng6, C. Zhao7, V. Thouret8, S. J. Oltmans9,10, S. C. Liu11, D. B. A. Jones12, S. D. Steenrod13,14, and M. R. Damon14,15 J. Huang et al.
  • 1National Institute of Aerospace, Hampton, VA, USA
  • 2NASA Langley Research Center, Hampton, VA, USA
  • 3Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
  • 4NASA Headquarters, Washington, D.C., USA
  • 5South China Institute of Environmental Science, Guangzhou, Guangdong, China
  • 6Chinese Academy of Meteorological Sciences, Beijing, China
  • 7Department of Atmospheric Science, Peking University, Beijing, China
  • 8Laboratoire d'Aérologie, UMR5560, Toulouse, France
  • 9CIRES, University of Colorado, Boulder, CO, USA
  • 10NOAA ESRL, Boulder, CO, USA
  • 11Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
  • 12Department of Physics, University of Toronto, Toronto, Ontario, Canada
  • 13Universities Space Research Association, Columbia, MD, USA
  • 14NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 15Science Systems and Applications Inc., Lanham, MD, USA
  • *now at: University of Washington, Seattle, WA, USA

Abstract. Ozone (O3) concentrations in the lower troposphere (LT) over Beijing have significantly increased over the past 2 decades as a result of rapid industrialization in China, with important implications for regional air quality and the photochemistry of the background troposphere. We characterize the vertical distribution of lower-tropospheric (0–6 km) O3 over Beijing using observations from 16 ozonesonde soundings during a field campaign in April–May 2005 and MOZAIC (Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft) over 13 days in the same period. We focus on the origin of LT O3 enhancements observed over Beijing, particularly in May. We use a global 3-D chemistry and transport model (GEOS-Chem CTM; GEOS – Goddard Earth Observing System) driven by assimilated meteorological fields to examine the transport pathways for O3 pollution and to quantify the sources contributing to O3 and its enhancements in the springtime LT over Beijing. Output from the Global Modeling Initiative (GMI) CTM is also used. High O3 concentrations (up to 94.7 ppbv) were frequently observed at the altitude of ~ 1.5–2 km. The CTMs captured the timing of the occurrences but significantly underestimated their magnitude. GEOS-Chem simulations and a case study showed that O3 produced in the Asian troposphere (especially from Asian anthropogenic pollution) made major contributions to the observed O3 enhancements. Contributions from anthropogenic pollution in the European and North American troposphere were reduced during these events, in contrast with days without O3 enhancements when contributions from Europe and North America were substantial. The O3 enhancements typically occurred under southerly wind and warmer conditions. It is suggested that an earlier onset of the Asian summer monsoon would cause more O3 enhancement events in the LT over the North China Plain in late spring and early summer.

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Short summary
High ozone concentrations (up to 94.7ppbv) were frequently observed at an altitude of ~1.5--2km over Beijing during April--May 2005. Ozone due to Asian anthropogenic pollution made major contributions to the observed ozone enhancements. These enhancements typically occurred under southerly wind and warmer conditions. An earlier onset of the Asian summer monsoon would cause more ozone enhancement events in the lower troposphere over the North China Plain in late spring and early summer.
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