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Distribution, variability and sources of tropospheric ozone over south China in spring: intensive ozonesonde measurements at five locations and modeling analysis

Zhang, Yiqiang; Liu, Hongyu; Crawford, James H.; Considine, David B.; Chan, Chuenyu; Oltmans, Samuel J.; Thouret, Valerie

Distribution, variability and sources of tropospheric ozone over south China in spring: intensive ozonesonde measurements at five locations and modeling analysis Thumbnail


Authors

Yiqiang Zhang

Hongyu Liu

James H. Crawford

David B. Considine

Chuenyu Chan

Samuel J. Oltmans

Valerie Thouret



Abstract

We examine the characteristics of the spatial distribution and variability of tropospheric ozone (O3) by analysis of 93 ozonesonde profiles obtained at five stations over south China (18–30 N) during a field campaign in April–May 2004. We use a global 3-D chemical transport model (GEOS-Chem) to interpret these characteristics and to quantify the sources of tropospheric O3 over south China during this period. The observed tropospheric O3 mixing ratios showed strong spatiotemporal variability due to a complex interplay of various dynamical and chemical processes. A prominent feature in the upper and middle troposphere (UT/MT) was the frequent occurrence of high O3 mixing ratios shown as tongues extending down from the lower stratosphere or as isolated layers at all stations. The model largely captured the observed pattern of day-to-day variability in tropospheric O3 mixing ratios at all stations, but often underestimated those tongues or isolated layers of O3 enhancements observed in the UT/MT, especially at low-latitude stations. We found that tropospheric O3 along the southeast China coast was mainly produced within Asia. Lightning NOx emissions (over South Asia and equatorial Africa) and/or stratospheric influences were responsible for major events of high O3 observed in the UT/MT at all stations. Underestimated contributions of these sources likely led to the model’s underestimate in the low-latitude UT/MT O3. This study emphasizes the need for improved understanding of lightning NOx emissions and stratospheric influences over the Eurasian and African continents and for better representation of these processes in current global models.

Journal Article Type Article
Acceptance Date May 7, 2012
Publication Date Jun 22, 2012
Deposit Date Nov 28, 2017
Publicly Available Date Nov 28, 2017
Journal Journal of Geophysical Research : Atmospheres
Electronic ISSN 2169-897X
Publisher American Geophysical Union
Peer Reviewed Peer Reviewed
Volume 117
Issue D12
DOI https://doi.org/10.1029/2012JD017498
Public URL https://nottingham-repository.worktribe.com/output/710468
Publisher URL https://doi.org/10.1029/2012JD017498
Additional Information Copyright @ AGU

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