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<front>
<journal-meta>
<journal-id journal-id-type="publisher">ACP</journal-id>
<journal-title-group>
<journal-title>Atmospheric Chemistry and Physics</journal-title>
<abbrev-journal-title abbrev-type="publisher">ACP</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">Atmos. Chem. Phys.</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1680-7324</issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acp-13-11005-2013</article-id>
<title-group>
<article-title>Inverse modeling of Texas NO&lt;sub&gt;x&lt;/sub&gt; emissions using space-based and ground-based NO&lt;sub&gt;2&lt;/sub&gt; observations</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Tang</surname>
<given-names>W.</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>Cohan</surname>
<given-names>D. S.</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>Lamsal</surname>
<given-names>L. N.</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Xiao</surname>
<given-names>X.</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>W.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Civil and Environmental Engineering, Rice University, 6100 Main Street MS 519, Houston, TX 77005, USA</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>NASA Goddard Space Flight Center, Greenbelt, MD, USA</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Goddard Earth Sciences Technology &amp; Research, Universities Space Research Association, Columbia, MD, USA</addr-line>
</aff>
<pub-date pub-type="epub">
<day>12</day>
<month>11</month>
<year>2013</year>
</pub-date>
<volume>13</volume>
<issue>21</issue>
<fpage>11005</fpage>
<lpage>11018</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2013 W. Tang et al.</copyright-statement>
<copyright-year>2013</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/3.0/">https://creativecommons.org/licenses/by/3.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://acp.copernicus.org/articles/13/11005/2013/acp-13-11005-2013.html">This article is available from https://acp.copernicus.org/articles/13/11005/2013/acp-13-11005-2013.html</self-uri>
<self-uri xlink:href="https://acp.copernicus.org/articles/13/11005/2013/acp-13-11005-2013.pdf">The full text article is available as a PDF file from https://acp.copernicus.org/articles/13/11005/2013/acp-13-11005-2013.pdf</self-uri>
<abstract>
<p>Inverse modeling of nitrogen oxide (NO&lt;sub&gt;x&lt;/sub&gt;) emissions using
satellite-based NO&lt;sub&gt;2&lt;/sub&gt; observations has become more prevalent in recent
years, but has rarely been applied to regulatory modeling at regional scales.
In this study, OMI satellite observations of NO&lt;sub&gt;2&lt;/sub&gt; column densities are
used to conduct inverse modeling of NO&lt;sub&gt;x&lt;/sub&gt; emission inventories for
two Texas State Implementation Plan (SIP) modeling episodes. Addition of
lightning, aircraft, and soil NO&lt;sub&gt;x&lt;/sub&gt; emissions to the regulatory
inventory narrowed but did not close the gap between modeled and
satellite-observed NO&lt;sub&gt;2&lt;/sub&gt; over rural regions. Satellite-based top-down emission
inventories are created with the regional Comprehensive Air Quality Model
with extensions (CAMx) using two techniques: the direct scaling method and
discrete Kalman filter (DKF) with decoupled direct method (DDM) sensitivity
analysis. The simulations with satellite-inverted inventories are compared to
the modeling results using the a priori inventory as well as an inventory
created by a ground-level NO&lt;sub&gt;2&lt;/sub&gt;-based DKF inversion. The DKF inversions
yield conflicting results: the satellite-based inversion scales up the a
priori NO&lt;sub&gt;x&lt;/sub&gt; emissions in most regions by factors of 1.02 to 1.84,
leading to 3–55% increase in modeled NO&lt;sub&gt;2&lt;/sub&gt; column densities and
1–7 ppb increase in ground 8 h ozone concentrations, while the
ground-based inversion indicates the a priori NO&lt;sub&gt;x&lt;/sub&gt; emissions should
be scaled by factors of 0.34 to 0.57 in each region. However, none of the
inversions improve the model performance in simulating aircraft-observed
NO&lt;sub&gt;2&lt;/sub&gt; or ground-level ozone (O&lt;sub&gt;3&lt;/sub&gt;) concentrations.</p>
</abstract>
<counts><page-count count="14"/></counts>
</article-meta>
</front>
<body/>
<back>
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