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Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China
Joint Authors
Zhou, Lihua
Zhang, Jing
Zheng, Xiaohui
Xue, Wenhao
Zhu, Siguang
Source
Issue
Vol. 2019, Issue 2019 (31 Dec. 2019), pp.1-14, 14 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2019-12-29
Country of Publication
Egypt
No. of Pages
14
Main Subjects
Abstract EN
Compared with other regions in China, air pollution on the North China Plain (NCP) is serious.
Fine particle pollution has been studied in-depth, but there is less research on long-term troposphere ozone (O3) variation.
This study focuses on the summer interannual tropospheric O3 variation on the NCP and its influential factors.
Our analysis relies on satellite observations (O3, nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and formaldehyde (HCHO), determined as vertical column density of the troposphere) and dynamical processes (El Niño-Southern Oscillation (ENSO), potential vorticity (PV), the quasibiennial oscillation (QBO), and East Asian summer monsoon index (EASMI)).
Our results show the vertical column density of tropospheric O3 has a transition from the increasing trend to decreasing trend during the summer of 2005–2016.
The summer series of tropospheric O3 show two distinct phases: the first phase (2005–2011), with an average growth rate of 0.55 ± 0.20 DU/yr, and a second phase (2012–2016), with an average reduction rate of 0.16 ± 0.23 DU/yr.
The tropospheric NO2 column in the NCP also has a transition from the increasing trend to decreasing trend during the summer of 2005–2016.
Tropospheric NO2 and CO column concentrations obtained from satellite observations indicate that emission reductions might be the main cause of the tropospheric O3 decrease.
Particularly, the reduction of nitrogen oxides (NOx) is more significant, and NO2 decreased by (0.45 ± 0.11) × 1015 molec·cm−2 per year in summer since 2012.
However, tropospheric column HCHO shows an increase of 0.05 × 1015 molec·cm−2 per year during the whole period of 2005 to 2016.
An O3-NOx-VOC sensitivity experiment in the NCP showed that the O3 is still in a NOx-saturated state in some heavily polluted cities, although the NOx emissions are decreasing overall.
In addition to the chemical reactions, atmospheric dynamic processes also have an effect on tropospheric O3.
Finally, we built a model to analyze the contributions of chemical processes and dynamic processes to the tropospheric O3 column in the NCP.
For the chemical process variables, 69.73% of the observed trend of tropospheric O3 could be explained by the NO2 tropospheric column.
Therefore, the reduction of tropospheric O3 since 2012 is associated with the reduction of NOx.
For the dynamical process variables, ENSO, PV, and EASMI can explain 60.64% of the observed trend of tropospheric O3.
This result indicates that the atmospheric circulation of the western Pacific Ocean in summer has a significant impact on the interannual trends of tropospheric O3 in the NCP.
It is also found that chemical processes had a more important impact on interannual tropospheric O3 than dynamic processes, although the dynamic processes cannot be neglected.
American Psychological Association (APA)
Zhou, Lihua& Zhang, Jing& Zheng, Xiaohui& Xue, Wenhao& Zhu, Siguang. 2019. Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China. Advances in Meteorology،Vol. 2019, no. 2019, pp.1-14.
https://search.emarefa.net/detail/BIM-1118594
Modern Language Association (MLA)
Zhou, Lihua…[et al.]. Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China. Advances in Meteorology No. 2019 (2019), pp.1-14.
https://search.emarefa.net/detail/BIM-1118594
American Medical Association (AMA)
Zhou, Lihua& Zhang, Jing& Zheng, Xiaohui& Xue, Wenhao& Zhu, Siguang. Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China. Advances in Meteorology. 2019. Vol. 2019, no. 2019, pp.1-14.
https://search.emarefa.net/detail/BIM-1118594
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-1118594