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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>
</journal-title-group>
<issn pub-type="epub">1680-7324</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/acp-7-121-2007</article-id>
<title-group>
<article-title>Photochemical modelling in the Po basin with focus on formaldehyde and ozone</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Liu</surname>
<given-names>L.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</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>Flatøy</surname>
<given-names>F.</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>Ordóñez</surname>
<given-names>C.</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Braathen</surname>
<given-names>G. O.</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>Hak</surname>
<given-names>C.</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Junkermann</surname>
<given-names>W.</given-names>
</name>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Andreani-Aksoyoglu</surname>
<given-names>S.</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Mellqvist</surname>
<given-names>J.</given-names>
</name>
<xref ref-type="aff" rid="aff7">
<sup>7</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Galle</surname>
<given-names>B.</given-names>
</name>
<xref ref-type="aff" rid="aff7">
<sup>7</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Prévôt</surname>
<given-names>A. S. H.</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Isaksen</surname>
<given-names>I. S. A.</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Norwegian Institute for Air Research, Kjeller, Norway</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>University of Oslo, Meteorology and Oceanography Section, Department of Geosciences, Oslo, Norway</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Bjerknes Centre for Climate Research, University of Bergen, Bergen, Norway</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Institute of Environmental Physics, Heidelberg, University of Heidelberg, Germany</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>Research Centre Karlsruhe, Institute for Meteorology and Climate Research, Garmisch Partenkichen, Germany</addr-line>
</aff>
<aff id="aff7">
<label>7</label>
<addr-line>Department of Radio and Space, Chalmers University of Technology, Göteborg, Sweden</addr-line>
</aff>
<pub-date pub-type="epub">
<day>11</day>
<month>01</month>
<year>2007</year>
</pub-date>
<volume>7</volume>
<issue>1</issue>
<fpage>121</fpage>
<lpage>137</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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<abstract>
<p>As part of the EU project FORMAT (Formaldehyde as a
Tracer of Oxidation in the Troposphere), a field campaign was carried out in
the vicinity of Milan during the summer of 2002. Results from a 3-D regional
chemical transport model (NILU RCTM) were used to interpret the observations
focusing primarily on HCHO and ozone. The performance of the model was
assessed by comparing model results with ground based and aircraft
measurements. The model results show good agreement with surface
measurements, and the model is able to reproduce the photochemical episodes
during fair weather days. The comparison indicates that the model can
represent well the HCHO concentrations as well as their temporal and spatial
variability. The relationship between HCHO and (O&lt;sub&gt;3&lt;/sub&gt;&amp;times;H&lt;sub&gt;2&lt;/sub&gt;O)
was used to validate the model ability to predict the HCHO concentrations.
Further analysis revealed the importance of the representativeness of
different instruments: in-situ concentrations might be locally enhanced by
emissions, while long path measurements over a forest can be influenced by
rapid formation of HCHO from isoprene. The model is able to capture the
plume from the city of Milan and the modelled levels agree generally well
with the aircraft measurements, although the wind fields used in the model
can lead to a displacement of the ozone plume. During the campaign period,
O&lt;sub&gt;3&lt;/sub&gt; levels were seldom higher than 80 ppb, the peak surface ozone maxima
reached 90 ppb. Those relatively low values can be explained by low
emissions during the August vacation and unstable weather conditions in this
period. The modelled &amp;Delta;O&lt;sub&gt;3&lt;/sub&gt;/&amp;Delta;NO&lt;sub&gt;z&lt;/sub&gt; slope at Alzate of
5.1 agrees well with the measured slope of 4.9.</p>
</abstract>
<counts><page-count count="17"/></counts>
</article-meta>
</front>
<body/>
<back>
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