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<front>
<journal-meta>
<journal-id journal-id-type="publisher">ACPD</journal-id>
<journal-title-group>
<journal-title>Atmospheric Chemistry and Physics Discussions</journal-title>
<abbrev-journal-title abbrev-type="publisher">ACPD</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">Atmos. Chem. Phys. Discuss.</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1680-7375</issn>
<publisher><publisher-name></publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acp-2020-708</article-id>
<title-group>
<article-title>Meteorological formation mechanism of regional transport in winter 
heavy air pollution events in the middle Yangtze River area, China</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Bai</surname>
<given-names>Yongqing</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Zhao</surname>
<given-names>Tianliang</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Zhou</surname>
<given-names>Yue</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Xiong</surname>
<given-names>Jie</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Hu</surname>
<given-names>Weiyang</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Gu</surname>
<given-names>Yao</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Liu</surname>
<given-names>Lin</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Kong</surname>
<given-names>Shaofei</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Zheng</surname>
<given-names>Huang</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Hubei Key Laboratory for Heavy Rain Monitoring and Warning Research, Institute of Heavy Rain, China Meteorological Administration, Wuhan 430205, China</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing 210044, China</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Department of Atmospheric Science, School of Environemtal Studies, China University of Geosciences (Wuhan), 430074</addr-line>
</aff>
<pub-date pub-type="epub">
<day>16</day>
<month>11</month>
<year>2020</year>
</pub-date>
<volume>2020</volume>
<fpage>1</fpage>
<lpage>32</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2020 Yongqing Bai et al.</copyright-statement>
<copyright-year>2020</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://acp.copernicus.org/preprints/acp-2020-708/">This article is available from https://acp.copernicus.org/preprints/acp-2020-708/</self-uri>
<self-uri xlink:href="https://acp.copernicus.org/preprints/acp-2020-708/acp-2020-708.pdf">The full text article is available as a PDF file from https://acp.copernicus.org/preprints/acp-2020-708/acp-2020-708.pdf</self-uri>
<abstract>
<p>&lt;p&gt;Anthropogenic emission, meteorological conditions, and regional transport 
are the three major factors influencing heavy air pollution in China. The Hunan and 
Hubei provinces in the middle Yangtze River region border China&apos;s main air pollution 
areas, serving as the hub of regional transport of air pollutants. The meteorological 
formation mechanism of regional transport of air pollutants on heavy air pollution in 
the Hunan and Hubei provinces still remain urgent to be addressed in depth. In this 
study, multivariate empirical orthogonal function (MV-EOF) analysis was performed 
to objectively select eight typical heavy pollution events in the two provinces that 
occured in January 2015&amp;ndash;2019. Based on the regional surface environment, 
meteorological network data, atmospheric sounding data, ERA-interim reanalysis data, 
and a numerical simulation experiment, this study investigated the pattern of regional 
transport of air pollutants in the two provinces and its mechanism of regional 
meteorological conditions. The results showed that transporting air pollutants mainly 
passed through two transport pathways, namely the Nanxiang Basin-Yunmeng Plain 
pathway and the Dabie Mountain&apos;s Hilly Area-Yunmeng Plain pathway, existing 
anomalous near-surface northerly winds in the two provinces and their upstream area 
accompanied by southward penetration of a shallow cold layer, all of which jointly 
provide a dynamic condition for regional air pollutant transport. The weak cold-air 
mass degenerated as it passed through the Hunan–Hubei Plain, causing warm air to accumulate in the near-surface layer of the downstream area, where winds slowed 
down and converged, buffering the air pollutant transport and resulting in pollutants 
accumulation; the near-surface atmosphere of the Hunan and Hubei provinces was a 
non-stagnant condition (dry intrusion of cold air, anomalous northerly winds, and 
positive anomalies of boundary-layer height), which is conducive to the horizontal 
transport of air pollutants. However, the mid-high layers, characterized by 
temperature inversion and the presence of a &lt;q&gt;warm lid&lt;/q&gt;, had a stable stratification, 
inhibiting the diffusion of air pollutants to the upper layers; there is an obvious 
longitudinal vertical circulation above the Hunan–Hubei Plain, which results in the 
sinking and accumulation of air pollutants, thereby promoting rapid accumulation of 
air pollutants in the Hunan and Hubei provinces. In addition, extended empirical 
orthogonal function (EEOF) analysis was performed, revealing a quasi-4-d periodic 
oscillation pattern of air pollutants transport in the Hunan and Hubei provinces, which 
provides a reference for early prediction of its regional transport. The findings are of 
practical value in broadening the scientific understanding of the differences in the 
formation mechanism of heavy atmospheric pollution between the various regions of 
China and promoting environmental and ecological protection of the middle Yangtze 
Basin.&lt;/p&gt;</p>
</abstract>
<counts><page-count count="32"/></counts>
<funding-group>
<award-group id="gs1">
<funding-source>National Natural Science Foundation of China</funding-source>
<award-id>41830965</award-id>
</award-group>
<award-group id="gs2">
<funding-source></funding-source>
<award-id>2016YFC0203304</award-id>
</award-group>
</funding-group>
</article-meta>
</front>
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