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<front>
<journal-meta>
<journal-id journal-id-type="publisher">CP</journal-id>
<journal-title-group>
<journal-title>Climate of the Past</journal-title>
<abbrev-journal-title abbrev-type="publisher">CP</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">Clim. Past</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1814-9332</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/cp-8-1839-2012</article-id>
<title-group>
<article-title>Duration of Greenland Stadial 22 and ice-gas &amp;Delta;age from counting of annual layers in Greenland NGRIP ice core</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Vallelonga</surname>
<given-names>P.</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>Bertagna</surname>
<given-names>G.</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>Blunier</surname>
<given-names>T.</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>Kjær</surname>
<given-names>H. A.</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>Popp</surname>
<given-names>T. J.</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>Rasmussen</surname>
<given-names>S. 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>Steffensen</surname>
<given-names>J. P.</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>Stowasser</surname>
<given-names>C.</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>Svensson</surname>
<given-names>A. 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>Warming</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>Winstrup</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>Bigler</surname>
<given-names>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>Kipfstuhl</surname>
<given-names>S.</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Centre for Ice and Climate &amp;ndash; Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Physics Institute, Climate and Environmental Physics and Oeschger Centre for Climate Change Research,  University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Alfred Wegener Institute, Glaciology, Colombusstrasse, 27568 Bremerhaven, Germany</addr-line>
</aff>
<pub-date pub-type="epub">
<day>20</day>
<month>11</month>
<year>2012</year>
</pub-date>
<volume>8</volume>
<issue>6</issue>
<fpage>1839</fpage>
<lpage>1847</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2012 P. Vallelonga et al.</copyright-statement>
<copyright-year>2012</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://cp.copernicus.org/articles/8/1839/2012/cp-8-1839-2012.html">This article is available from https://cp.copernicus.org/articles/8/1839/2012/cp-8-1839-2012.html</self-uri>
<self-uri xlink:href="https://cp.copernicus.org/articles/8/1839/2012/cp-8-1839-2012.pdf">The full text article is available as a PDF file from https://cp.copernicus.org/articles/8/1839/2012/cp-8-1839-2012.pdf</self-uri>
<abstract>
<p>High-resolution measurements of chemical impurities and methane
concentrations in Greenland ice core samples from the early glacial period
allow the extension of annual-layer counted chronologies and the improvement
of gas age-ice age difference (&amp;Delta;age) essential to the
synchronization of ice core records. We report high-resolution measurements
of a 50 m section of the NorthGRIP ice core and corresponding annual
layer thicknesses in order to constrain the duration of the Greenland
Stadial 22 (GS-22) between Greenland Interstadials (GIs) 21 and 22, for
which inconsistent durations and ages have been reported from Greenland and
Antarctic ice core records as well as European speleothems. Depending on the
chronology used, GS-22 occurred between approximately 89 (end of GI-22) and
83 kyr b2k (onset of GI-21). From annual layer counting, we find that GS-22
lasted between 2696 and 3092 years and was followed by a GI-21 pre-cursor
event lasting between 331 and 369 yr. Our layer-based counting agrees
with the duration of stadial 22 as determined from the NALPS speleothem
record (3250 &amp;plusmn; 526 yr) but not with that of the &lt;i&gt;GICC05modelext&lt;/i&gt; chronology (2620 yr) or
an alternative chronology based on gas-marker synchronization to EPICA
Dronning Maud Land ice core. These results show that &lt;i&gt;GICC05modelext&lt;/i&gt; overestimates
accumulation and/or underestimates thinning in this early part of the last
glacial period. We also revise the possible ranges of NorthGRIP &amp;Delta;depth (5.49 to 5.85 m) and &amp;Delta;age (498 to 601 yr) at the warming onset
of GI-21 as well as the &amp;Delta;age range at the onset of the GI-21
precursor warming (523 to 654 yr), observing that temperature (represented by
the &amp;delta;&lt;sup&gt;15&lt;/sup&gt;N proxy) increases before CH&lt;sub&gt;4&lt;/sub&gt; concentration by no
more than a few decades.</p>
</abstract>
<counts><page-count count="9"/></counts>
</article-meta>
</front>
<body/>
<back>
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