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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>
</journal-title-group>
<issn pub-type="epub">1680-7375</issn>
<publisher><publisher-name>Copernicus GmbH</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acpd-8-16713-2008</article-id>
<title-group>
<article-title>Tropospheric NO&lt;sub&gt;2&lt;/sub&gt; column densities deduced from zenith-sky DOAS measurements in Shanghai, China, and their application to satellite validation</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Chen</surname>
<given-names>D.</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>Zhou</surname>
<given-names>B.</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>Beirle</surname>
<given-names>S.</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>Chen</surname>
<given-names>L. M.</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>Wagner</surname>
<given-names>T.</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Environmental Science and Engineering, Fudan University, China</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Max Planck Institute for Chemistry, Mainz, Germany</addr-line>
</aff>
<pub-date pub-type="epub">
<day>03</day>
<month>09</month>
<year>2008</year>
</pub-date>
<volume>8</volume>
<issue>4</issue>
<fpage>16713</fpage>
<lpage>16762</lpage>
<permissions>
<license xlink:type="simple">
<license-p>This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</license-p>
</license>
</permissions>
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<self-uri xlink:href="http://www.atmos-chem-phys-discuss.net/8/16713/2008/acpd-8-16713-2008.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/8/16713/2008/acpd-8-16713-2008.pdf</self-uri>
<abstract>
<p>Zenith-sky scattered sunlight observations using differential optical
absorption spectroscopy (DOAS) technique were carried out in Shanghai, China
(31.3&amp;deg; N, 121.5&amp;deg; E) since December 2006. At this polluted urban site,
the measurement provided NO&lt;sub&gt;2&lt;/sub&gt; total columns in the daytime. Here, we
present a new method to extract time series of tropospheric vertical column
densities (VCD) of NO&lt;sub&gt;2&lt;/sub&gt; from these observations. The derived
tropospheric NO&lt;sub&gt;2&lt;/sub&gt; VCD is an important quantity for the estimation of
emissions and for the validation of satellite observations. Our method makes
use of assumptions on the relative NO&lt;sub&gt;2&lt;/sub&gt; height profiles and on the
diurnal variation of the stratospheric NO&lt;sub&gt;2&lt;/sub&gt; VCD. The influence of these
parameters on the retrieved tropospheric NO&lt;sub&gt;2&lt;/sub&gt; VCD is discussed; for a
polluted site like Shanghai, the accuracy of our method is estimated to be
&amp;lt;20% for solar zenith angle (SZA) lower than 85&amp;deg;. From
simultaneously performed long-path DOAS measurement, the NO&lt;sub&gt;2&lt;/sub&gt; surface
concentration at the same site was observed and the corresponding
tropospheric NO&lt;sub&gt;2&lt;/sub&gt; VCD was estimated using the assumed seasonal NO&lt;sub&gt;2&lt;/sub&gt;
profiles in the planetary boundary layer (PBL). By making a comparison
between the tropospheric NO&lt;sub&gt;2&lt;/sub&gt; VCD from zenith-sky and long-path DOAS
measurements, it was found that the former provided more realistic
information about total tropospheric pollution than the latter, so it&apos;s more
suitable for satellite data validation than the in situ measurement. A
comparison between the tropospheric NO&lt;sub&gt;2&lt;/sub&gt; VCD from ground-based
zenith-sky measurement and SCIAMACHY was also made. Satellite validation for
a strongly polluted area is highly needed, but exhibits also a great
challenge. Our comparison showed good agreement, considering in particular
the different spatial resolutions between the two measurements.</p>
</abstract>
<counts><page-count count="50"/></counts>
</article-meta>
</front>
<body/>
<back>
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