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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-6-12199-2006</article-id>
<title-group>
<article-title>The latitude dependence and probability distribution of polar mesospheric turbulence</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Rapp</surname>
<given-names>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>Becker</surname>
<given-names>E.</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>Strelnikov</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>Lübken</surname>
<given-names>F.-J.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Leibniz Institute of Atmospheric Physics, Schlossstr. 6, 18225 Kühlungsborn, Germany</addr-line>
</aff>
<pub-date pub-type="epub">
<day>28</day>
<month>11</month>
<year>2006</year>
</pub-date>
<volume>6</volume>
<issue>6</issue>
<fpage>12199</fpage>
<lpage>12216</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/6/12199/2006/acpd-6-12199-2006.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/6/12199/2006/acpd-6-12199-2006.pdf</self-uri>
<abstract>
<p>We consider in-situ observations and results from a global
circulation model to study the latitude dependence and
probability distribution of polar mesospheric turbulence. A
comparison of summer observations at 69&amp;deg; N and 79&amp;deg; N shows
that mesospheric turbulence weakens towards the summer pole.
Furthermore, these data suggest that at both latitudes in about
~70% of all samples there are non-turbulent altitude
bins in the considered altitude range between 70 and 95 km. The
remaining 30% with detectable turbulence show an
approximately log-normal distribution of dissipation rates. A
low-resolution model version with a gravity wave (GW)
parameterization explains the observed latitude dependence as a
consequence of a downshift of the breaking levels towards the
summer pole and an accompanying decay of turbulent heating per
unit mass. When we do not use a GW parameterization but employ a
high spatial resolution instead to simulate GW effects
explicitly, the model predicts a similar latitudinal dependence
with weakening turbulence towards the summer pole. In addition,
the model also produces a log-normal distribution of dissipation
rates. The simulated probability distribution is more narrow
than in the observations since the model resolves at most
mid-frequency GWs, whereas real turbulence is also excited by
smaller-scale disturbances. The GW resolving simulation suggests
a weaker tropospheric GW source at polar latitudes as the
dominating mechanism for the latitudinal dependence.</p>
</abstract>
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