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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" dtd-version="3.0" xml:lang="en">
<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-3-1919-2003</article-id>
<title-group>
<article-title>CO&lt;sub&gt;2&lt;/sub&gt; flux history 1982–2001 inferred from atmospheric data using a global inversion of atmospheric transport</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Rödenbeck</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>Houweling</surname>
<given-names>S.</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>Gloor</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>Heimann</surname>
<given-names>M.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Max Planck Institute for Biogeochemistry, Postfach 10 01 64, D-07701 Jena, Germany</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>National Institute for Space Research (SRON), Princetonplein 5, NL-3584 CC Utrecht, The Netherlands</addr-line>
</aff>
<pub-date pub-type="epub">
<day>05</day>
<month>11</month>
<year>2003</year>
</pub-date>
<volume>3</volume>
<issue>6</issue>
<fpage>1919</fpage>
<lpage>1964</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.net/3/1919/2003/acp-3-1919-2003.html">This article is available from http://www.atmos-chem-phys.net/3/1919/2003/acp-3-1919-2003.html</self-uri>
<self-uri xlink:href="http://www.atmos-chem-phys.net/3/1919/2003/acp-3-1919-2003.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys.net/3/1919/2003/acp-3-1919-2003.pdf</self-uri>
<abstract>
<p>Based on about 20 years of
      NOAA/CMDL&apos;s atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentration data and a global atmospheric tracer transport model,
      we estimate interannual variations and spatial patterns of surface CO&lt;sub&gt;2&lt;/sub&gt;
      fluxes in the period 01/1982-12/2000, by using a time-dependent Bayesian inversion technique.
      To increase the reliability of the estimated temporal features, particular care is exerted
      towards the selection of data records that are homogeneous in time. Fluxes are estimated on a grid-scale resolution
      (~8º latitude x 10º longitude), constrained by a-priori spatial correlations,
      and then integrated over different sets of regions. The transport model is driven by interannually varying
      re-analyzed meteorological fields. We make consistent use of unsmoothed measurements.
      In agreement with previous studies, land fluxes are estimated to be the main driver of
      interannual variations in the global CO&lt;sub&gt;2&lt;/sub&gt; fluxes, with the pace predominantly being set by the
      El Niño/La Niña contrast. An exception is a 2-3 year period of increased sink of
      atmospheric carbon after Mt.&amp;nbsp; Pinatubo&apos;s volcanic eruption in 1991. The largest differences in fluxes between
      El Niño and La Niña are found in the tropical land regions, the main share being due to the Amazon basin.
      The flux variations for the Post-Pinatubo period, the 1997/1998 El Niño, and
      the 1999 La Niña events are exploited to investigate relations between CO&lt;sub&gt;2&lt;/sub&gt;
      fluxes and climate forcing. A rough comparison points to anomalies in precipitation
      as a prominent climate factor for short-term variability of tropical land fluxes,
      both through their role on NPP and through promoting fire in case of droughts.
      Some large flux anomalies seem to be directly related to large biomass burning events recorded by satellite observation.
      Global ocean carbon uptake shows a trend similar to the one expected if ocean uptake scales proportional to
      the anthropogenic atmospheric CO&lt;sub&gt;2&lt;/sub&gt; perturbation. In contrast to temporal variations,
      the longterm spatial flux distribution can be inferred with lesser robustness only.
      The tentative pattern estimated by the present inversion exhibits a northern hemisphere land sink
      on the order of 0.4 PgC/yr (for 01/1996-12/1999, non-fossil fuel carbon only)
      that is mainly confined to North America. Southern hemisphere land regions are carbon neutral,
      while the tropical land regions are taking up carbon (e.g., at a rate of
      0.8 PgC/yr during 01/1996-12/1999). Ocean fluxes show larger uptake in the Northern mid to high latitudes
      than in the Southern mid latitude regions, in contrast to the estimates by
      Takahashi et al. (1999) based on in-situ measurements. On a regional basis, results that differ the most from previous estimates
      are large carbon uptake of 1 to 1.5 PgC/yr by the Southern temperate Pacific ocean region,
      weak outgassing from the Southern ocean, and a carbon source from eastern Europe.</p>
</abstract>
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