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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>GÃ¶ttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/acpd-11-11959-2011</article-id>
<title-group>
<article-title>Snow optical properties at Dome C, Antarctica â€“ implications for snow emissions and snow chemistry of reactive nitrogen</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>France</surname>
<given-names>J. L.</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>King</surname>
<given-names>M. 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>Frey</surname>
<given-names>M. M.</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>Erbland</surname>
<given-names>J.</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>Picard</surname>
<given-names>G.</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>MacArthur</surname>
<given-names>A.</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>Savarino</surname>
<given-names>J.</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>British Antarctic Survey, Highcross, Madingley Road, Cambridge CB3 0ET, UK</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>UJF-Grenoble 1/CNRS-INSU, Laboratoire de Glaciologie et GÃ©ophysique de l&apos;Environnement UMR 5183, St.-Martin-d&apos;HÃ¨res, France</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>NERC Field Spectroscopy Facility, Grant Institute, School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3JW, UK</addr-line>
</aff>
<pub-date pub-type="epub">
<day>18</day>
<month>04</month>
<year>2011</year>
</pub-date>
<volume>11</volume>
<issue>4</issue>
<fpage>11959</fpage>
<lpage>11993</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>
<self-uri xlink:href="http://www.atmos-chem-phys-discuss.net/11/11959/2011/acpd-11-11959-2011.html">This article is available from http://www.atmos-chem-phys-discuss.net/11/11959/2011/acpd-11-11959-2011.html</self-uri>
<self-uri xlink:href="http://www.atmos-chem-phys-discuss.net/11/11959/2011/acpd-11-11959-2011.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/11/11959/2011/acpd-11-11959-2011.pdf</self-uri>
<abstract>
<p>Measurements of $e$-folding depth, nadir reflectivity and stratigraphy of the
snowpack around Concordia station (Dome C, 75.10Â° S, 123.31Â° E) were
undertaken and used to determine wavelength dependent coefficients (350 nm
to 550 nm) for light scattering and absorption and to calculate potential
fluxes of nitrogen dioxide (NO&lt;sub&gt;2&lt;/sub&gt;) from the snowpack due to nitrate
photolysis within the snowpack. The stratigraphy of the top 80 cm of Dome C
snowpack generally consists of three main layers: a surface of soft
windpack (not ubiquitous), a hard windpack and a hoar-like layer beneath
the windpack(s). The $e$-folding depths are ~10 cm for the two windpack
layers and ~20 cm for the hoar-like layer for solar radiation at a
wavelength of 400 nm, about a factor 2â€“4 larger than previous model
estimates for South Pole. Depth integrated photochemical reaction rates of
nitrate photolysis in the Dome C snowpack were calculated to give molecular
fluxes of NO&lt;sub&gt;2&lt;/sub&gt; of 5.3&amp;times;10&lt;sup&gt;12&lt;/sup&gt; molecules m&lt;sup&gt;âˆ’2&lt;/sup&gt; s&lt;sup&gt;âˆ’1&lt;/sup&gt;,
2.3&amp;times;10&lt;sup&gt;12&lt;/sup&gt; molecules m&lt;sup&gt;âˆ’2&lt;/sup&gt; s&lt;sup&gt;âˆ’1&lt;/sup&gt;  and
8&amp;times;10&lt;sup&gt;11&lt;/sup&gt; molecules m&lt;sup&gt;âˆ’2&lt;/sup&gt; s&lt;sup&gt;âˆ’1&lt;/sup&gt; for solar zenith angles of 60Â°,
70Â° and 80Â° respectively for clear sky conditions using the TUV-snow
radiative-transfer model. Depending upon the snowpack stratigraphy, a
minimum of 85% of the NO&lt;sub&gt;2&lt;/sub&gt; originates from within the top 20 cm of
the Dome C snowpack. It is found that on a multi-annual scale, nitrate
photolysis can remove up to 80% of nitrate from surface snow, confirming
independent isotopic evidence that photolysis is an important driver of
nitrate loss occurring in the EAIS snowpack. However, the model cannot
account for the total observed nitrate loss of 90â€“95% or the shape of the
observed nitrate depth profile. A more complete model will need to include
also physical processes such as evaporation, re-deposition or diffusion
between the quasi-liquid layer on snow grains and firn air to account for
the discrepancies.</p>
</abstract>
<counts><page-count count="35"/></counts>
</article-meta>
</front>
<body/>
<back>
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