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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-7-9717-2007</article-id>
<title-group>
<article-title>Evaluating model performance of an ensemble-based chemical data assimilation system during INTEX-B field mission</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>A. F. Arellano Jr.</surname>
<given-names></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>Raeder</surname>
<given-names>K.</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>Anderson</surname>
<given-names>J. L.</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>Hess</surname>
<given-names>P. 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>Emmons</surname>
<given-names>L. K.</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>Edwards</surname>
<given-names>D. 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>Pfister</surname>
<given-names>G. 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>Campos</surname>
<given-names>T. 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>Sachse</surname>
<given-names>G. W.</given-names>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Atmospheric Chemistry Division, Earth and Sun Systems Laboratory, National Center for Atmospheric Research, PO Box 3000, Boulder, Colorado 80307-3000, USA</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Institute for Mathematics Applied to Geosciences, Computational and Information Systems Laboratory, National Center for Atmospheric Research, PO Box 3000, Boulder, Colorado, 80307-3000, USA</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Chemistry and Dynamics Branch, NASA Langley Research Center, Hampton, Virginia, 23681-2199, USA</addr-line>
</aff>
<pub-date pub-type="epub">
<day>05</day>
<month>07</month>
<year>2007</year>
</pub-date>
<volume>7</volume>
<issue>4</issue>
<fpage>9717</fpage>
<lpage>9767</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/7/9717/2007/acpd-7-9717-2007.html">This article is available from http://www.atmos-chem-phys-discuss.net/7/9717/2007/acpd-7-9717-2007.html</self-uri>
<self-uri xlink:href="http://www.atmos-chem-phys-discuss.net/7/9717/2007/acpd-7-9717-2007.pdf">The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/7/9717/2007/acpd-7-9717-2007.pdf</self-uri>
<abstract>
<p>We present a global chemical data assimilation system using a global
atmosphere model, the Community Atmosphere Model (CAM3) with simplified
chemistry and the Data Assimilation Research Testbed (DART) assimilation
package. DART is a community software facility for assimilation studies
using the ensemble Kalman filter approach. Here, we apply the assimilation
system to constrain global tropospheric carbon monoxide (CO) by assimilating
meteorological observations of temperature and horizontal wind velocity and
satellite CO retrievals from the Measurement of Pollution in the Troposphere
(MOPITT) satellite instrument. We verify the system performance using
independent CO observations taken on board the NSF/NCAR C-130 and NASA DC-8
aircrafts during the April 2006 part of the Intercontinental Chemical
Transport Experiment (INTEX-B). Our evaluations show that MOPITT data
assimilation provides significant improvements in terms of capturing the
observed CO variability relative to no MOPITT assimilation (i.e. the
correlation improves from 0.62 to 0.71, significant at 99% confidence).
The assimilation provides evidence of median CO loading of about 150 ppbv at
700 hPa over the NE Pacific during April 2006. This is marginally higher
than the modeled CO with no MOPITT assimilation (~140 ppbv). Our
ensemble-based estimates of model uncertainty also show model overprediction
over the source region (i.e. China) and underprediction over the NE Pacific,
suggesting model errors that cannot be readily explained by emissions alone.
These results have important implications for improving regional chemical
forecasts and for inverse modeling of CO sources and further demonstrates
the utility of the assimilation system in comparing non-coincident
measurements, e.g. comparing satellite retrievals of CO with in-situ
aircraft measurements.</p>
</abstract>
<counts><page-count count="51"/></counts>
</article-meta>
</front>
<body/>
<back>
<ref-list>
<title>References</title>
<ref id="ref1">
<label>1</label><mixed-citation publication-type="other" xlink:type="simple"> Allen, D. J., Kasibhatla, P. S., Thompson, A. M., et al.: Transport-induced interannual variability of carbon monoxide determined using a chemistry and transport model, J. Geophys. Res., 101, 28 655&amp;ndash;28 670, doi:10.1029/96JD02984, 1996. </mixed-citation>
</ref>
<ref id="ref2">
<label>2</label><mixed-citation publication-type="other" xlink:type="simple"> Anderson, J. L. and Anderson ,S. L.: A Monte Carlo implementation of the nonlinear filtering problem to produce ensemble assimilations and forecasts, Mon. Weather Rev., 127, 2741&amp;ndash;2758, 1999. </mixed-citation>
</ref>
<ref id="ref3">
<label>3</label><mixed-citation publication-type="other" xlink:type="simple"> Anderson, J. L.: An ensemble adjustment Kalman Filter for data assimilation, Mon. Weather Rev., 129, 2884&amp;ndash;2903, 2001. </mixed-citation>
</ref>
<ref id="ref4">
<label>4</label><mixed-citation publication-type="other" xlink:type="simple"> Anderson, J. L.: Exploring the need for localization in ensemble data assimilation using an hierarchical ensemble filter, Physica D, doi:10.1016/j.physd.2006.02.011, 2007a. </mixed-citation>
</ref>
<ref id="ref5">
<label>5</label><mixed-citation publication-type="other" xlink:type="simple"> Anderson, J. L.: An adaptive covariance inflation error correction algorithm for ensemble filters, Tellus A, 59, 210&amp;ndash;224, 2007b. </mixed-citation>
</ref>
<ref id="ref6">
<label>6</label><mixed-citation publication-type="other" xlink:type="simple"> Arellano A. F., Kasibhatla, P. S, Giglio, L., et al.: Top-down estimates of global CO sources using MOPITT measurements, Geophys. Res. Lett., 31, L01104, doi:10.1029/2003GL018609, 2004. </mixed-citation>
</ref>
<ref id="ref7">
<label>7</label><mixed-citation publication-type="other" xlink:type="simple"> Arellano A. F. and Hess, P. G.: Sensitivity of top-down estimates of CO sources to GCTM transport, Geophys. Res. Lett., 33, L21807, doi:10.1029/2006GL027371, 2006. </mixed-citation>
</ref>
<ref id="ref8">
<label>8</label><mixed-citation publication-type="other" xlink:type="simple"> Auger, L. and Tangborn, A. V.: A Wavelet-Based Reduced Rank Kalman Filter for Assimilation of Stratospheric Chemical Tracer Observations, Mon. Wea. Rev., 132, 1220&amp;ndash;1237, 2004. </mixed-citation>
</ref>
<ref id="ref9">
<label>9</label><mixed-citation publication-type="other" xlink:type="simple"> Bey, I., Jacob, D. J., Logan, J. A., and Yantosca, R. M.: Asian chemical outflow to the Pacific in spring: Origins, pathways, and budgets, J. Geophys. Res., 106, 23 097&amp;ndash;23 114, 10.1029/2001JD000806, 2001. </mixed-citation>
</ref>
<ref id="ref10">
<label>10</label><mixed-citation publication-type="other" xlink:type="simple"> Chai, T., Carmichael, G. R., Sandu, A., et al.: Chemical data assimilation of Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft measurements, J. Geophys. Res., 111, D02301, doi:10.1029/2005JD005883, 2006. </mixed-citation>
</ref>
<ref id="ref11">
<label>11</label><mixed-citation publication-type="other" xlink:type="simple"> Clerbaux, C., Hadji-Lazaro, J., Hauglustaine, D., et al.: Assimilation of carbon monoxide measured from satellite in a three-dimensional chemistry-transport model, J. Geophys. Res., 106, 15 385&amp;ndash;15 394, 10.1029/2000JD900682, 2001. </mixed-citation>
</ref>
<ref id="ref12">
<label>12</label><mixed-citation publication-type="other" xlink:type="simple"> Collins, W. D., Rasch, P. J., Eaton, B. E., et al.: Simulating aerosols using a chemical transport model with assimilation of satellite aerosol retrievals: Methodology for INDOEX, J. Geophys. Res., 106, 7313&amp;ndash;7336, doi:10.1029/2000JD900507, 2001. </mixed-citation>
</ref>
<ref id="ref13">
<label>13</label><mixed-citation publication-type="other" xlink:type="simple"> Collins, W. D., Bitz, C. M., Blackmon, M. L., et al.: The Formulation and atmospheric simulation of the Community Atmosphere Model Version 3 (CAM3), J. Climate, 19(11), 2144&amp;ndash;2161, 2006. </mixed-citation>
</ref>
<ref id="ref14">
<label>14</label><mixed-citation publication-type="other" xlink:type="simple"> Dee, D. P.: Bias and data assimilation, Q. J. Roy. Meteorol. Soc., 131(613), 3323&amp;ndash;3343, 2005. </mixed-citation>
</ref>
<ref id="ref15">
<label>15</label><mixed-citation publication-type="other" xlink:type="simple"> Deeter, M. N., Emmons, L. K., Edwards, D. P., et al.: Vertical resolution and information content of CO profiles retrieved by MOPITT, Geophys. Res. Lett., 31, L15112, doi:10.1029/2004GL020235, 2004. </mixed-citation>
</ref>
<ref id="ref16">
<label>16</label><mixed-citation publication-type="other" xlink:type="simple"> Dethof, A. and Hólm, E.: Ozone assimilation in the ERA-40 reanalysis project, Q. J. R. Meteorol. Soc., 130, 2851&amp;ndash;2872, 2004. </mixed-citation>
</ref>
<ref id="ref17">
<label>17</label><mixed-citation publication-type="other" xlink:type="simple"> Eben, K., Juru\cs, P., Resler, J., et al.: An ensemble Kalman filter for short-term forecasting of tropospheric ozone concentrations, Q. J. R. Meteorol. Soc., 131, 3313&amp;ndash;3322, 2005. </mixed-citation>
</ref>
<ref id="ref18">
<label>18</label><mixed-citation publication-type="other" xlink:type="simple"> Elbern, H., Strunk, A., Schmidt, H., and Talagrand, O.: Emission rate and chemical state estimation by 4-dimensional variational inversion, Atmos. Chem. Phys., 7, 1&amp;ndash;59, 2007. </mixed-citation>
</ref>
<ref id="ref19">
<label>19</label><mixed-citation publication-type="other" xlink:type="simple"> Elbern, H. and Schmidt, H.: A four-dimensional variational chemistry data assimilation scheme for Eulerian chemistry transport modeling, J. Geophys. Res., 104, 18 583&amp;ndash;18 598, 1999. </mixed-citation>
</ref>
<ref id="ref20">
<label>20</label><mixed-citation publication-type="other" xlink:type="simple"> Elbern, H., Schmidt, H., Talagrand, O., and Ebel, A.: 4D-variational data assimilation with an adjoint air quality model for emission analysis, Environ. Modell. Software, 15, 539&amp;ndash;548, 2000. </mixed-citation>
</ref>
<ref id="ref21">
<label>21</label><mixed-citation publication-type="other" xlink:type="simple"> Emmons L. K., Deeter, M. N., Gille, J. C., et al.: Validation of Measurements of Pollution in the Troposphere (MOPITT) CO retrievals with aircraft in situ profiles, J. Geophys. Res., 109, D03309, doi:10.1029/2003JD004101, 2004. </mixed-citation>
</ref>
<ref id="ref22">
<label>22</label><mixed-citation publication-type="other" xlink:type="simple"> Emmons, L. K., Pfister, G. G., Edwards, D. P., et al.: Measurements of Pollution in the Troposphere (MOPITT) validation exercises during summer 2004 field campaigns over North America, J. Geophys. Res., 112, D12S02, doi:10.1029/2006JD007833, 2007. </mixed-citation>
</ref>
<ref id="ref23">
<label>23</label><mixed-citation publication-type="other" xlink:type="simple"> Engelen R. J. and McNally, A. P.: Estimating atmospheric CO2 from advanced infrared satellite radiances within an operational four-dimensional variational (4D-Var) data assimilation system: Results and validation, J. Geophys. Res., 110, D18305, doi:10.1029/2005JD005982, 2005. </mixed-citation>
</ref>
<ref id="ref24">
<label>24</label><mixed-citation publication-type="other" xlink:type="simple"> Eskes, H. J., Van Velthoven, P. F. J., Valks, P. J. M., et al.: Assimilation of GOME total ozone satellite observations in a three-dimensional tracer transport model, Q. J. R. Meteorol. Soc., 129, 1663&amp;ndash;1681, 2003. </mixed-citation>
</ref>
<ref id="ref25">
<label>25</label><mixed-citation publication-type="other" xlink:type="simple"> Evensen, G.: Sequential data assimilation with a nonlinear quasi-geostrophic model using Monte-Carlo methods to forecast error statistics, J. Geophys., Res., 99, 10 143&amp;ndash;10 162, 1994. </mixed-citation>
</ref>
<ref id="ref26">
<label>26</label><mixed-citation publication-type="other" xlink:type="simple"> Fisher, M., and Lary, D.J.: Lagrangian four-dimensional variational data assimilation of chemical species, Q. J. R. Meteorol. Soc., 121, 1681-1704, 1995. </mixed-citation>
</ref>
<ref id="ref27">
<label>27</label><mixed-citation publication-type="other" xlink:type="simple"> Frankenberg, C., Meirink, J. F., Bergamaschi, P., et al.: Satellite chartography of atmospheric methane from SCIAMACHY on board ENVISAT: Analysis of the years 2003 and 2004, J. Geophys. Res., 111, D07303, doi:10.1029/2005JD006235, 2006. </mixed-citation>
</ref>
<ref id="ref28">
<label>28</label><mixed-citation publication-type="other" xlink:type="simple"> Gaspari, G. and Cohn, S. E.: Construction of correlation functions in two and three dimensions, Q. J. R. Meteorol. Soc., 125, 723&amp;ndash;758, 1999. </mixed-citation>
</ref>
<ref id="ref29">
<label>29</label><mixed-citation publication-type="other" xlink:type="simple"> Giglio, L., Csiszar, I., and Justice, C. O.: Global distribution and seasonality of active fires as observed with the Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) sensors, J. Geophys. Res., 111, G02016, doi:10.1029/2005JG000142, 2006. </mixed-citation>
</ref>
<ref id="ref30">
<label>30</label><mixed-citation publication-type="other" xlink:type="simple"> Granier, C., Müller, J.-F. , Pétron, G., et al.: A three-dimensional study of the global CO budget, Chemosphere, Global. Change Sci., 1, 255&amp;ndash;261, 1999. </mixed-citation>
</ref>
<ref id="ref31">
<label>31</label><mixed-citation publication-type="other" xlink:type="simple"> Hamill, T. M., Whitaker, J., and Snyder, C.: Distance-dependent filtering of background error covariance estimates in an ensemble Kalman filter, Mon. Wea. Rev., 129, 2776&amp;ndash;2790, 2001. </mixed-citation>
</ref>
<ref id="ref32">
<label>32</label><mixed-citation publication-type="other" xlink:type="simple"> Hanea, R. G., Velders, G. J. M., and Heemink, A.: Data assimilation of ground-level ozone in Europe with a Kalman filter and chemistry transport model, J. Geophys. Res., 109, D10302, doi:10.1029/2003JD004283, 2004. </mixed-citation>
</ref>
<ref id="ref33">
<label>33</label><mixed-citation publication-type="other" xlink:type="simple"> Houtekamer, P. L. and Mitchell, H. L.: Data assimilation using an ensemble Kalman filter technique, Mon. Wea. Rev., 126, 796&amp;ndash;811, 1998. </mixed-citation>
</ref>
<ref id="ref34">
<label>34</label><mixed-citation publication-type="other" xlink:type="simple"> Houtekamer, P. L., Mitchell, H. L., Pellerin, G., et al.: Atmospheric data assimilation with an ensemble Kalman filter: Results with real observations, Mon. Weather Rev., 133(3), 604&amp;ndash;620, 2005. </mixed-citation>
</ref>
<ref id="ref35">
<label>35</label><mixed-citation publication-type="other" xlink:type="simple"> Jaffe, D., Anderson, T., Covert, D., et al.: Transport of Asian air pollution to North America, Geophys. Res. Lett., 26(6), 711&amp;ndash;714, doi:10.1029/1999GL900100, 1999. </mixed-citation>
</ref>
<ref id="ref36">
<label>36</label><mixed-citation publication-type="other" xlink:type="simple"> Juckes, M. N. and Lawrence, B. N.: Data Assimilation for Reanalyses: potential gains from full use of post-analysis-time observations, Tellus A 58(2), 171&amp;ndash;178, 2006. </mixed-citation>
</ref>
<ref id="ref37">
<label>37</label><mixed-citation publication-type="other" xlink:type="simple"> Khattatov, B. V., Lamarque, J.-F. , Lyjak, L. V., et al.: Assimilation of satellite observations of long-lived chemical species in global chemistry transport models, J. Geophys. Res., 105(D23), 29 135&amp;ndash;29 144, 10.1029/2000JD900466, 2000. </mixed-citation>
</ref>
<ref id="ref38">
<label>38</label><mixed-citation publication-type="other" xlink:type="simple"> Lamarque, J.-F., Khattatov, B. V., Gille, J. C., and Brasseur, G. P.: Assimilation of Measurement of Air Pollution from space (MAPS) CO in a global three-dimensional model, J. Geophys. Res., 104(D21), 26 209&amp;ndash;26 218, doi:10.1029/1999JD900807, 1999. </mixed-citation>
</ref>
<ref id="ref39">
<label>39</label><mixed-citation publication-type="other" xlink:type="simple"> Lamarque J.-F. and Gille, J. C.: Improving the modeling of error variance evolution in the assimilation of chemical species: Application to MOPITT data, Geophys. Res. Lett., 30(9), 1470, doi:10.1029/2003GL016994, 2003. </mixed-citation>
</ref>
<ref id="ref40">
<label>40</label><mixed-citation publication-type="other" xlink:type="simple"> Lamarque J.-F., Khattatov, B. V., and Gille, J. C.: Constraining tropospheric ozone column through data assimilation, J. Geophys. Res., 107(D22), 4651, doi:10.1029/2001JD001249, 2002. </mixed-citation>
</ref>
<ref id="ref41">
<label>41</label><mixed-citation publication-type="other" xlink:type="simple"> Lamarque, J. F., Khattatov, B. V.,Yudin, V., et al.: Application of a bias estimator for the improved assimilation of Measurements of Pollution in the Troposphere (MOPITT) carbon monoxide retrievals, J. Geophys. Res., 109, D16304, doi:10.1029/2003JD004466, 2004. </mixed-citation>
</ref>
<ref id="ref42">
<label>42</label><mixed-citation publication-type="other" xlink:type="simple"> Lamarque, J.-F., Kiehl, J. T., Hess, P. G., et al.: Response of a coupled chemistry climate model to changes in aerosol emissions: Global impact on the hydrological cycle and the tropospheric burdens of OH, ozone, and NOx, Geophys. Res. Lett., 32, doi:10.1029/2005GL023419, 2005. </mixed-citation>
</ref>
<ref id="ref43">
<label>43</label><mixed-citation publication-type="other" xlink:type="simple"> Lary, D. J.: Data assimilation: a powerful tool for atmospheric chemistry, Philos. Trans. R. Soc. Lond. Ser. A. Math Phys., 357(1763), 3445&amp;ndash;3457, 1999. </mixed-citation>
</ref>
<ref id="ref44">
<label>44</label><mixed-citation publication-type="other" xlink:type="simple"> Lawrence, M. G., Hov, Ø., Beekmann, M., et al.: The Chemical Weather, Environ. Chem., 2, 6&amp;ndash;8, doi:10.1071/EN05014, 2005. </mixed-citation>
</ref>
<ref id="ref45">
<label>45</label><mixed-citation publication-type="other" xlink:type="simple"> Levelt, P. F., Khattatov, B. V., Gille, J. C., et al.: Assimilation of MLS ozone measurements in the global three-dimensional chemistry transport model ROSE, Geophys. Res. Lett., 25(24), 4493&amp;ndash;4496, 10.1029/1998GL900152, 1998. </mixed-citation>
</ref>
<ref id="ref46">
<label>46</label><mixed-citation publication-type="other" xlink:type="simple"> Liang Q., Jaeglé, L., Jaffe, D. A., et al.: Long-range transport of Asian pollution to the northeast Pacific: Seasonal variations and transport pathways of carbon monoxide, J. Geophys. Res., 109, D23S07, doi:10.1029/2003JD004402, 2004. </mixed-citation>
</ref>
<ref id="ref47">
<label>47</label><mixed-citation publication-type="other" xlink:type="simple"> Logan, J. A., Prather, M. J., Wofsy, S. C., and McElroy, M. B.: Tropospheric chemistry: A global perspective, J. Geophys. Res., 86, 7210&amp;ndash;7254, 1981. </mixed-citation>
</ref>
<ref id="ref48">
<label>48</label><mixed-citation publication-type="other" xlink:type="simple"> Lorenc, A. C.: The potential of the ensemble Kalman . lter for NWP&amp;ndash;-a comparison with 4D-Var, Q. J. R. Meteorol. Soc., 129, 3183&amp;ndash;3203, 2003. </mixed-citation>
</ref>
<ref id="ref49">
<label>49</label><mixed-citation publication-type="other" xlink:type="simple"> McLaughlin, D., O&apos;neill, A., Derber, J., and Kamachi, M.: Opportunities for enhanced collaboration within the data assimilation community, Q. J. R. Meteorol. Soc., 131, 3683&amp;ndash;3693, 2005. </mixed-citation>
</ref>
<ref id="ref50">
<label>50</label><mixed-citation publication-type="other" xlink:type="simple"> Menard, R., Cohn, S. E., Chang, L.-P., and Lyster, P. M.: Assimilation of Stratospheric Chemical Tracer Observations Using a Kalman Filter, Part I: Formulation, Mon. Wea. Rev, 128, 2654&amp;ndash;2671, 2000. </mixed-citation>
</ref>
<ref id="ref51">
<label>51</label><mixed-citation publication-type="other" xlink:type="simple"> Muller, J. F. and T. Stavrakou, T.: Inversion of CO and NOx emissions using the adjoint of the IMAGES model, Atmos. Chem. Phys., 5, 1157&amp;ndash;1186, 2005. </mixed-citation>
</ref>
<ref id="ref52">
<label>52</label><mixed-citation publication-type="other" xlink:type="simple"> Novelli, P. C., Masarie, K. A., Lang, P. M., et al.: Reanalysis of tropospheric CO trends: Effects of the 1997&amp;ndash;1998 wildfires, J. Geophys. Res., 108(D15), 4464, doi:10.1029/2002JD003031, 2003. </mixed-citation>
</ref>
<ref id="ref53">
<label>53</label><mixed-citation publication-type="other" xlink:type="simple"> Peters, W., Miller, J. B., Whitaker, J., et al.: An ensemble data assimilation system to estimate CO&lt;sub&gt;2&lt;/sub&gt; surface fluxes from atmospheric trace gas observations, J. Geophys. Res., 110, D24304, doi:10.1029/2005JD006157, 2005. </mixed-citation>
</ref>
<ref id="ref54">
<label>54</label><mixed-citation publication-type="other" xlink:type="simple"> Pétron G., Granier, C., Khattatov, B., et al.: Monthly CO surface sources inventory based on the 2000&amp;ndash;2001 MOPITT satellite data, Geophys. Res. Lett., 31, L21107, doi:10.1029/2004GL020560, 2004. </mixed-citation>
</ref>
<ref id="ref55">
<label>55</label><mixed-citation publication-type="other" xlink:type="simple"> Rabier, F.: Overview of global data assimilation developments in numerical weather-prediction centres, Q. J. R. Meteorol. Soc., 131, 3215&amp;ndash;3233, 2005. </mixed-citation>
</ref>
<ref id="ref56">
<label>56</label><mixed-citation publication-type="other" xlink:type="simple"> Rasch, P. J., Coleman, D. B., Mahowald, N., et al.: Characteristics of atmospheric transport using three numerical formulations for atmospheric dynamics in a single GCM framework, J. Climate, 19(11), 2243&amp;ndash;2266, 2006. </mixed-citation>
</ref>
<ref id="ref57">
<label>57</label><mixed-citation publication-type="other" xlink:type="simple"> Rasch, P. J., Collins, W. D., and Eaton, B. E.: Understanding the Indian Ocean Experiment (INDOEX) aerosol distributions with an aerosol assimilation, J. Geophys. Res., 106(D7), 7337&amp;ndash;7356, doi:10.1029/2000JD900508, 2001. </mixed-citation>
</ref>
<ref id="ref58">
<label>58</label><mixed-citation publication-type="other" xlink:type="simple"> Rayner P. J., Scholze, M., Knorr, W., et al.: Two decades of terrestrial carbon fluxes from a carbon cycle data assimilation system (CCDAS), Global Biogeochem. Cycles, 19, GB2026, doi:10.1029/2004GB002254, 2005. </mixed-citation>
</ref>
<ref id="ref59">
<label>59</label><mixed-citation publication-type="other" xlink:type="simple"> Sandu, A., Constantinescu, E. M., Liao, W., et al.: Ensemble-based data assimilation for atmospheric chemical transport models, Lect. Notes in Comp. Sci., 3515, 648&amp;ndash;-655, 2005. </mixed-citation>
</ref>
<ref id="ref60">
<label>60</label><mixed-citation publication-type="other" xlink:type="simple"> Sekiyama, T. T. and Shibata, K.: Predictability of Total Ozone Using a Global Three-Dimensional Chemical Transport Model Coupled with the MRI/JMA98 GCM, Mon. Wea. Rev. 133(8), 2262, 2005. </mixed-citation>
</ref>
<ref id="ref61">
<label>61</label><mixed-citation publication-type="other" xlink:type="simple"> Stajner, I., Riishøjgaard, L. P., and Rood, R.: The GEOS ozone data assimilation system: specification of error statistics, Q. J. R. Meteorol. Soc., 127, 1069&amp;ndash;1094, 2001. </mixed-citation>
</ref>
<ref id="ref62">
<label>62</label><mixed-citation publication-type="other" xlink:type="simple"> Tippet, M. K., Anderson, J. L., Bishop, C. H., et al.: Ensemble square root filters, Mon. Weather Rev., 131, 1485&amp;ndash;1490, 2003. </mixed-citation>
</ref>
<ref id="ref63">
<label>63</label><mixed-citation publication-type="other" xlink:type="simple"> Van Loon, M., Builtjes, P. J. H., and Segers, A.: Data assimilation of ozone in the atmospheric transport chemistry model LOTOS, Env. Mod. and Softw., 15, 603&amp;ndash;609, 2000. </mixed-citation>
</ref>
<ref id="ref64">
<label>64</label><mixed-citation publication-type="other" xlink:type="simple"> van der Werf, G. R., Randerson, J. T., Giglio, L., et al.: Interannual variability in biomass burning emissions from 1997 to 2004, Atmos. Chem. Phys., 6, 3423&amp;ndash;3441, 2006. </mixed-citation>
</ref>
<ref id="ref65">
<label>65</label><mixed-citation publication-type="other" xlink:type="simple"> Wang, K. Y., Lary, D. J., Shallcross, D. E., et al.: A review on the use of the adjoint method in four-dimensional atmospheric-chemistry data assimilation, Q. J. R. Meteorol. Soc., 127(576), 2181&amp;ndash;2204, 2001. </mixed-citation>
</ref>
<ref id="ref66">
<label>66</label><mixed-citation publication-type="other" xlink:type="simple"> Yienger, J., Galanter, M., Holloway, T. A., et al.: The episodic nature of air pollution transport from Asia to North America, J. Geophys. Res., 105(D22), 26 931&amp;ndash;26 946, 10.1029/2000JD900309, 2000. </mixed-citation>
</ref>
<ref id="ref67">
<label>67</label><mixed-citation publication-type="other" xlink:type="simple"> Yudin, V. A., Pétron, G., Lamarque, J.-F., et al.: Assimilation of the 2000&amp;ndash;2001 CO MOPITT retrievals with optimized surface emissions, Geophys. Res. Lett., 31, L20105, doi:10.1029/2004GL021037, 2004. </mixed-citation>
</ref>
</ref-list>
</back>
</article>