Origin of springtime ozone enhancements in the lower troposphere over Beijing: in situ measurements and model analysis
Item
Title (Dublin Core)
Origin of springtime ozone enhancements in the lower troposphere over Beijing: in situ measurements and model analysis
Description (Dublin Core)
Ozone (O<sub>3</sub>) 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) O<sub>3</sub> 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 O<sub>3</sub> 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 O<sub>3</sub> pollution and to quantify the sources contributing to O<sub>3</sub> and its enhancements in the springtime LT over Beijing. Output from the Global Modeling Initiative (GMI) CTM is also used. High O<sub>3</sub> 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 O<sub>3</sub> produced in the Asian troposphere (especially from Asian anthropogenic pollution) made major contributions to the observed O<sub>3</sub> enhancements. Contributions from anthropogenic pollution in the European and North American troposphere were reduced during these events, in contrast with days without O<sub>3</sub> enhancements when contributions from Europe and North America were substantial. The O<sub>3</sub> enhancements typically occurred under southerly wind and warmer conditions. It is suggested that an earlier onset of the Asian summer monsoon would cause more O<sub>3</sub> enhancement events in the LT over the North China Plain in late spring and early summer.
Creator (Dublin Core)
Huang, J.
Liu, H.
Crawford, J. H.
Chan, C.
Considine, D. B.
Zhang, Y.
Zheng, X.
Zhao, C.
Thouret, V.
Oltmans, S. J.
Liu, S. C.
Jones, D. B. A.
Steenrod, S. D.
Damon, M. R.
Date (Dublin Core)
2018-09-06
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-15-5161-2015
https://acp.copernicus.org/articles/15/5161/2015/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
