Tropospheric ozone climatology over Beijing: analysis of aircraft data from the MOZAIC program
Ozone (O<sub>3</sub>) profiles recorded over Beijing from 1995 to 2005 by the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program were analyzed to provide a first climatology of tropospheric O<sub>3</sub> over Be...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2008-01-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/8/1/2008/acp-8-1-2008.pdf |
| Summary: | Ozone (O<sub>3</sub>) profiles recorded over Beijing from 1995 to 2005 by the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program were analyzed to provide a first climatology of tropospheric O<sub>3</sub> over Beijing and the North China Plains (NCPs), one of the most populated and polluted regions in China. A pooled method was adopted in the data analysis to reduce the influence of irregular sampling frequency. The tropospheric O<sub>3</sub> over Beijing shows a seasonal and vertical distribution typical of mid-latitude locations in the Northern Hemisphere, but has higher daytime concentrations in the lower troposphere, when compared to New York City, Tokyo, and Paris at similar latitude. The tropospheric O<sub>3</sub> over Beijing exhibits a common summer maximum and a winter minimum, with a broad summer maximum in the middle troposphere and a narrower early summer (June) peak in the lower troposphere. Examination of meteorological and satellite data suggests that the lower tropospheric O<sub>3</sub> maximum in June is a result of strong photochemical production, transport of regional pollution, and possibly also more intense burnings of biomass in Central-Eastern China. Trajectory analysis indicates that in summer the regional pollution from the NCPs, maybe mixed with urban plumes from Beijing, played important roles on the high O<sub>3</sub> concentrations in the boundary layer, but had limited impact on the O<sub>3</sub> concentrations in the middle troposphere. A comparison of the data recorded before and after 2000 reveals that O<sub>3</sub> in the lower troposphere over Beijing had a strong positive trend (approximately 2% per year from 1995 to 2005) in contrast to a flat or a decreasing trend over Tokyo, New York City, and Paris, indicating worsening photochemical pollution in Beijing and the NCPs. |
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| ISSN: | 1680-7316 1680-7324 |