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<DIV jQuery1369382637383="4"><CITE><SPAN
class="slug-metadata-note ahead-of-print">Published Online <SPAN
class=slug-ahead-of-print-date>April 4 2013</SPAN><BR></SPAN><ABBR
class=slug-jnl-abbrev title=Science>Science</ABBR><SPAN class=slug-pub-date
itemprop="datePublished"> 24 May 2013: </SPAN><BR><SPAN class=slug-vol>Vol. 340
</SPAN><SPAN class=slug-issue>no. 6135 </SPAN><SPAN class=slug-pages>pp. 945-950
</SPAN><BR>DOI: <SPAN class=slug-doi
title=10.1126/science.1234210>10.1126/science.1234210 </SPAN></CITE></DIV>
<DIV jQuery1369382637383="4"><CITE><SPAN class=slug-doi
title=10.1126/science.1234210></SPAN></CITE> </DIV></DIV>
<DIV id=article-title-1 class="article abstract-view " jQuery1369382637383="6"
itemprop="headline" sizset="0" sizcache="1"><FONT size=4>Annually Resolved Ice
Core Records of Tropical Climate Variability over the Past ~1800
Years</FONT></DIV>
<DIV>
<DIV id=contrib-1 class=contributor jQuery1369382637383="6"
itemscope="itemscope" itemtype="http://schema.org/Person" itemprop="author"
sizset="0" sizcache="0"><SPAN class=name itemprop="name"><A class=name-search
href="http://www.sciencemag.org/search?author1=L.+G.+Thompson&sortspec=date&submit=Submit">L.
G. Thompson</A></SPAN><A id=xref-aff-1-1 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-1"
jQuery1369382637383="20"><SUP>1</SUP></A><SPAN class=xref-sep>,</SPAN><A
id=xref-aff-2-1 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-2"
jQuery1369382637383="21"><SUP>2</SUP></A><SPAN class=xref-sep>,</SPAN><A
id=xref-corresp-1-1 class=xref-corresp
href="http://www.sciencemag.org/content/340/6135/945.abstract#corresp-1">*</A>,
<SPAN class=name itemprop="name"><A class=name-search
href="http://www.sciencemag.org/search?author1=E.+Mosley-Thompson&sortspec=date&submit=Submit">E.
Mosley-Thompson</A></SPAN><A id=xref-aff-1-2 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-1"
jQuery1369382637383="22"><SUP>1</SUP></A><SPAN class=xref-sep>,</SPAN><A
id=xref-aff-3-1 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-3"
jQuery1369382637383="23"><SUP>3</SUP></A>, <SPAN class=name itemprop="name"><A
class=name-search
href="http://www.sciencemag.org/search?author1=M.+E.+Davis&sortspec=date&submit=Submit">M.
E. Davis</A></SPAN><A id=xref-aff-1-3 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-1"
jQuery1369382637383="24"><SUP>1</SUP></A>, <SPAN class=name itemprop="name"><A
class=name-search
href="http://www.sciencemag.org/search?author1=V.+S.+Zagorodnov&sortspec=date&submit=Submit">V.
S. Zagorodnov</A></SPAN><A id=xref-aff-1-4 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-1"
jQuery1369382637383="25"><SUP>1</SUP></A>, <SPAN class=name itemprop="name"><A
class=name-search
href="http://www.sciencemag.org/search?author1=I.+M.+Howat&sortspec=date&submit=Submit">I.
M. Howat</A></SPAN><A id=xref-aff-1-5 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-1"
jQuery1369382637383="26"><SUP>1</SUP></A><SPAN class=xref-sep>,</SPAN><A
id=xref-aff-2-2 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-2"
jQuery1369382637383="27"><SUP>2</SUP></A>, <SPAN class=name itemprop="name"><A
class=name-search
href="http://www.sciencemag.org/search?author1=V.+N.+Mikhalenko&sortspec=date&submit=Submit">V.
N. Mikhalenko</A></SPAN><A id=xref-aff-4-1 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-4"
jQuery1369382637383="28"><SUP>4</SUP></A>, <SPAN class=name><A class=name-search
href="http://www.sciencemag.org/search?author1=P.-N.+Lin&sortspec=date&submit=Submit">P.-N.
Lin</A></SPAN><A id=xref-aff-1-6 class=xref-aff
href="http://www.sciencemag.org/content/340/6135/945.abstract#aff-1"
jQuery1369382637383="29"><SUP>1</SUP></A><SUP></SUP></DIV>
<DIV class=contributor jQuery1369382637383="6" itemscope="itemscope"
itemtype="http://schema.org/Person" itemprop="author" sizset="0"
sizcache="0"><SUP>1</SUP>Byrd Polar Research Center, The Ohio State University,
Columbus, OH 43210, USA. <SUP>2</SUP>School of Earth Sciences, The Ohio State
University, Columbus, OH 43210, USA. <SUP>3</SUP>Department of Geography, The
Ohio State University, Columbus, OH 43210, USA. <SUP>4</SUP>Institute of
Geography, Russian Academy of Sciences, Moscow, Russia. Corresponding author.
E-mail: <A href="mailto:thompson.3@osu.edu">thompson.3@osu.edu</A></DIV>
<DIV class=contributor jQuery1369382637383="6" itemscope="itemscope"
itemtype="http://schema.org/Person" itemprop="author" sizset="0"
sizcache="0"> </DIV>
<DIV class="article abstract-view " jQuery1369382637383="47"
itemprop="articleBody" sizset="0" sizcache="1"><A class=current
href="http://www.sciencemag.org/content/340/6135/tab-abstract"
jQuery1369382637383="38"><FONT
color=#000000><STRONG>Abstract</STRONG></FONT></A></DIV>
<DIV class="panes tab-boxed-content" jQuery1369382637383="6"
itemprop="articleBody" sizset="0" sizcache="1">
<DIV style="DISPLAY: block" id=abstract-3 class="section abstract"
jQuery1369382637383="45">
<P id=p-3>Ice cores from low latitudes can provide a wealth of unique
information about past climate in the tropics, but they are difficult to recover
and few exist. Here, we report annually resolved ice core records from the
Quelccaya ice cap (5670 meters above sea level) in Peru that extend back ~1800
years and provide a high-resolution record of climate variability there. Oxygen
isotopic ratios (δ<SUP>18</SUP>O) are linked to sea surface temperatures in the
tropical eastern Pacific, whereas concentrations of ammonium and nitrate
document the dominant role played by the migration of the Intertropical
Convergence Zone in the region of the tropical Andes. Quelccaya continues to
retreat and thin. Radiocarbon dates on wetland plants exposed along its
retreating margins indicate that it has not been smaller for at least six
millennia. </P></DIV>
<DIV style="DISPLAY: none" id=abstract-1 class="section editor-summary"
jQuery1369382637383="46" itemprop="description">
<H2><FONT size=2>Quelccaya Ice Cap</FONT></H2>
<P id=p-1>Ice cores drilled in the ice sheets of Greenland and Antarctica are
some of the most important sources of information about the paleoclimate of high
latitudes. Comparable records from the tropics are rare, however, because there
are so few locations at which long-lived, undisturbed ice can be found.
<STRONG>Thompson <EM>et al.</EM></STRONG> (p. <A
href="http://www.sciencemag.org/lookup/doi/10.1126/science.1234210">945</A>,
published online 4 April) report results obtained from one of the few such
sites, the Quelccaya ice cap in the Peruvian Andes. The annually resolved data,
extending back 1800 years, provide a detailed chronicle of changes in the
isotopic composition of the oxygen in the ice, <U>which are related to the sea
surface temperature of the water's source</U>. Analyses of a collection of major
ions such as ammonium and nitrate reveal how atmospheric circulation in the
region varied over that period. Finally, the radiocarbon content of ancient
plants—recently exposed by the retreat of the ice sheet—reveals that Quelccaya
has not been smaller for at least six thousand years. </P></DIV></DIV>
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