Distribution, variability and sources of tropospheric ozone over south China in spring: Intensive ozonesonde measurements at five locations and modeling analysis
Distribution, variability and sources of tropospheric ozone over south China in spring: Intensive ozonesonde measurements at five locations and modeling analysis
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DOI：
10.1029/2012jd017498
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发表时间：
2012-06
影响因子：
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通讯作者：
Y. Zhang;Y. Zhang;Hongyu Liu;J. Crawford;D. Considine;D. Considine;C. Chan;S. Oltmans;S. Oltmans;V. Thouret
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文献类型：
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作者：
Y. Zhang;Y. Zhang;Hongyu Liu;J. Crawford;D. Considine;D. Considine;C. Chan;S. Oltmans;S. Oltmans;V. Thouret
通过对2004年4 - 5月在中国南方（18-30°N） 5个站点获得的93个臭氧探测剖面的分析，探讨了对流层臭氧（O3）的空间分布和变异特征。我们使用全球三维化学输送模式（GEOS-Chem）来解释这些特征，并量化了这一时期中国南方对流层O3的来源。观测到的对流层O3混合比由于各种动力和化学过程的复杂相互作用而表现出强烈的时空变异性。对流层中高层（UT/MT）的一个显著特征是高臭氧混合比的频繁出现，表现为从平流层低处向下延伸的舌状物或在所有站点都表现为孤立层。该模式在很大程度上捕获了所有台站观测到的对流层臭氧混合比的逐日变化模式，但往往低估了在UT/MT观测到的臭氧增强的方言或孤立层，特别是在低纬度台站。研究发现，中国东南沿海对流层O3主要产生于亚洲地区。闪电NOx排放（在南亚和赤道非洲上空）和/或平流层影响是UT/MT在所有站点观测到的主要高臭氧事件的原因。低估了这些源的贡献可能导致模式低估了低纬度UT/MT O3。这项研究强调有必要改进对闪电氮氧化物排放和对欧亚和非洲大陆平流层影响的了解，并在目前的全球模式中更好地代表这些过程。
[1] 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 O3mixing 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 O3enhancements 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 O3observed 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.