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<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>
<abbrev-journal-title abbrev-type="nlm-ta">Atmos. Chem. Phys.</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">1680-7324</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/acp-6-2057-2006</article-id>
<title-group>
<article-title>Impact of transatlantic transport episodes on summertime ozone in Europe</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Guerova</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>Bey</surname>
<given-names>I.</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>Attié</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>Martin</surname>
<given-names>R. V.</given-names>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Cui</surname>
<given-names>J.</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Sprenger</surname>
<given-names>M.</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Laboratoire de Modélisation de la Chimie Atmosphérique, \&apos;{E}cole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Laboratoire d&apos;Aérologie, Observatoire Midi Pyrénées, Toulouse, France</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Canada</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology Zurich (ETHZ), Zurich, Switzerland</addr-line>
</aff>
<pub-date pub-type="epub">
<day>20</day>
<month>06</month>
<year>2006</year>
</pub-date>
<volume>6</volume>
<issue>8</issue>
<fpage>2057</fpage>
<lpage>2072</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2006 G. Guerova et al.</copyright-statement>
<copyright-year>2006</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.5 Generic License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by-nc-sa/2.5/">https://creativecommons.org/licenses/by-nc-sa/2.5/</ext-link></license-p>
</license>
</permissions>
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<abstract>
<p>This paper reports on the transport of ozone (O&lt;sub&gt;3&lt;/sub&gt;) and related species over
the North Atlantic ocean and its impact on Europe. Measurements of nitrogen
dioxide (NO&lt;sub&gt;2&lt;/sub&gt;) and carbon monoxide (CO) columns from the GOME and MOPITT
satellite instruments, respectively, are used in conjunction with the
GEOS-CHEM global model of transport and tropospheric chemistry to identify
the major events of long range transport that reach Europe over the course of
summer 2000. Sensitivity model simulations are used to analyse observed O&lt;sub&gt;3&lt;/sub&gt;
distributions with respect to the impact of long range transport events. For
that purpose, we used in-situ O&lt;sub&gt;3&lt;/sub&gt; observations taken at the mountain site of
Jungfraujoch as well as O&lt;sub&gt;3&lt;/sub&gt; vertical profiles taken in the vicinity of
central European cities. Over the course of summer 2000, we identified 9
major episodes of transatlantic pollution transport; 7 events are associated
with transient cyclones while 2 events occur through zonal transport (e.g. by
advection in the strong low-level westerly winds established in summer
between the Azores anticyclone and transient cyclones). We find that on
average three episodes occur per month with the strongest ones being in June.
The number and frequency of long range transport events that reach Europe are
driven by the position and strength of the Azores anticyclone. Model
sensitivity simulations indicate that the summer mean North American O&lt;sub&gt;3&lt;/sub&gt;
contribution ranges from 3 to 5 ppb (7&amp;ndash;11%) in the planetary boundary layer
and 10 to 13 ppb (18&amp;ndash;23%) in the middle and upper troposphere. During
particular episodes, North American sources can result in O&lt;sub&gt;3&lt;/sub&gt; enhancements up
to 25&amp;ndash;28 ppb in the layer between 800&amp;ndash;600 hPa and 10&amp;ndash;12 ppb in the boundary
layer. The impact of the zonal transport events on O&lt;sub&gt;3&lt;/sub&gt; distribution over
Europe is more clearly seen below 700 hPa as they tend to transport pollution
at lower levels while the events associated with transient cyclones are more
likely to have an impact on the middle and upper troposphere (i.e. above 600 hPa).
The air mass origins found in the GEOS-CHEM model are clearly confirmed
by back trajectory analyses. During most of the 9 events, a strong
contribution in North American O&lt;sub&gt;3&lt;/sub&gt; is in general associated with only little
European O&lt;sub&gt;3&lt;/sub&gt; and vice-versa (in particular at the Jungfraujoch). A
substantial North American contribution (e.g., 30% or higher) to O&lt;sub&gt;3&lt;/sub&gt; over
Europe does not always result in pronounced O&lt;sub&gt;3&lt;/sub&gt; enhancements in the
observations during our period of study.</p>
</abstract>
<counts><page-count count="16"/></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"> Auvray, M. and Bey, I.: A modeling study of the background ozone over Europe: Origin and interannual variability, J. Geophys. Res., 110, D11303, https://doi.org/10.1029/2004JD005503, 2005. </mixed-citation>
</ref>
<ref id="ref2">
<label>2</label><mixed-citation publication-type="other" xlink:type="simple"> Baltensperger, U., Gaeggeler, H W., Jost, D T., Lugauer, M., Schikowski, M., Weingartenr, E., and Seibert, P.: Aerosol climatology at the high-alpine site Jungfraujoch, Switzerland, J. Geophys. Res., 102, 19 707-19 715, 1997. </mixed-citation>
</ref>
<ref id="ref3">
<label>3</label><mixed-citation publication-type="other" xlink:type="simple"> Bey, I., Jacob, D J., Logan, J A., and Yantosca, R M.: Global modeling of tropospheric chemistry with assimilated meteorology: Model description and evaluation, J. Geophys. Res., 106, 23 073-23 095, 2001. </mixed-citation>
</ref>
<ref id="ref4">
<label>4</label><mixed-citation publication-type="other" xlink:type="simple"> Burrows, J P., Weber, M., Buchwitz, M., Rozanov, V., Ladstätter-Weibenmayer, A., Richter, A., Debeek, R., Hoogen, R., Bramstedt, K., Eichmann, K.-U., Eisinger, M., and Perner, D.: The Global Ozone Monitoring Experiment (GOME): Mission concept and first results, J. Atmos. Sci., 56, 151-175, 1999. </mixed-citation>
</ref>
<ref id="ref5">
<label>5</label><mixed-citation publication-type="other" xlink:type="simple"> Chin, M., Ginoux, P., Kinne, S., Torres, O., Holben, B., Duncan, B., Martin, R., Logan, J., Higurashi, A., and Nakajima, T.: Tropospheric aerosol optical thickness from GOCART model and comparisons with satellite and sunphotometer measurements, J. Atmos. Sci., 59, 461-483, 2002. </mixed-citation>
</ref>
<ref id="ref6">
<label>6</label><mixed-citation publication-type="other" xlink:type="simple">Cooper, O R., Moody, J L., Parrish, D D., Trainer, M., Ryerson, T B., Holloway, J S., Huebler, G., Fehsenfeld, F C., Oltmans, S J., and Evans, M J.: Trace gas signatures of the airstreams within North Atlantic cyclones: Case studies from the North Atlantic Regional Experiment (NARE-97) aircraft intensive, J. Geophys. Res., 106(D6), 5437, https://doi.org/10.1029/2000JD900574, 2001.</mixed-citation>
</ref>
<ref id="ref7">
<label>7</label><mixed-citation publication-type="other" xlink:type="simple"> Cooper, O R., Forster, C., Parrish, D., Trainer, M., Dunlea, E., Ryerson, T., Huebler, G., Fehsenfeld, F., Nicks, D., Holloway, J., de~Gouw, J., Warneke, C., Roberts, J M., Flocke, F., and Moody, J.: A case study of transpacific warm conveyor belt transport: Influence of merging airstreams on trace gas import to North America, J. Geophys. Res., 109(D23), 508, https://doi.org/10.1029/2003JD003624, 2004. </mixed-citation>
</ref>
<ref id="ref8">
<label>8</label><mixed-citation publication-type="other" xlink:type="simple"> Deeter, M N., Emmons, L K., Francis, G L., Edwards, D P., Gille, J C., Warner, J X., Khattatov, B., Ziskin, D., Lamarque, J.-F., Ho, S.-P., Yudin, V., Atti\&apos;e, J.-L., Packman, D., Chen, J., Mao, D., and Drummond, J R.: Operational carbon monoxide retrieval algorithm and selected results for the MOPITT instrument, J. Geophys. Res., 108, 4399, https://doi.org/10.1029/2003JD003186, 2003. </mixed-citation>
</ref>
<ref id="ref9">
<label>9</label><mixed-citation publication-type="other" xlink:type="simple"> Duncan, B. and Bey, I.: A modeling study of export pathways of pollution from Europe: Seasonal and interannual variations., J. Geophys. Res., 109(D08), 301, https://doi.org/10.1029/2003JD004079, 2004. </mixed-citation>
</ref>
<ref id="ref10">
<label>10</label><mixed-citation publication-type="other" xlink:type="simple"> Duncan, B., Martin, R V., Staudt, A C., Yevich, R., and Logan, J A.: Interannual and seasonnal variability of biomass burning emissions constrained by satellite observations, J. Geophys. Res., 108, 4100, https://doi.org/10.1029/2002JD002378, 2003. </mixed-citation>
</ref>
<ref id="ref11">
<label>11</label><mixed-citation publication-type="other" xlink:type="simple"> Fay, B., Glaab, H., and Schrodin, R. I.: Evaluation of Eulerian and Lagrangian atmosphere transport models at Deutscher Wetterdienst using ANATEX surface tracer data., Atmos. Environ., 29, 2485-2497, 1995. </mixed-citation>
</ref>
<ref id="ref12">
<label>12</label><mixed-citation publication-type="other" xlink:type="simple"> Fiore, A., Jacob, D., Liu, H., Yantosca, R., Fairlie, T., and Li, Q.: Variability in surface ozone background over the United States: Implications for air quality policy, J. Geophys. Res., 108, 4787, https://doi.org/10.1029/2003JD003855, 2003. </mixed-citation>
</ref>
<ref id="ref13">
<label>13</label><mixed-citation publication-type="other" xlink:type="simple"> Fiore, A M., Jacob, D., Bey, I., Yantosca, R., Field, B., Fusco, A., and Wilkinson, J.: Background ozone over the United States in summer: origin,trend, and contribution to pollution episodes, J. Geophys. Res., 107, 4275, https://doi.org/10.1029/2001JD000982, 2002. </mixed-citation>
</ref>
<ref id="ref14">
<label>14</label><mixed-citation publication-type="other" xlink:type="simple"> Fusco, A C. and Logan, J A.: Analysis of 1970-1995 trends in tropospheric ozone at Northern Hemisphere midlatitudes with the GEOS-CHEM model, J. Geophys. Res., 108, 4449, https://doi.org/10.1029/2002JD002742, 2003. </mixed-citation>
</ref>
<ref id="ref15">
<label>15</label><mixed-citation publication-type="other" xlink:type="simple"> Hudman, R., Jacob, D., Cooper, O., Evans, M., Heald, C., Park, R., Fehsenfeld, F., Flocke, F., Holloway, J., Huebler, G., Kita, K., Koike, M., Kondo, Y., Neuman, A., Nowak, J., Oltmans, S., Parrish, D., Roberts, J., and Ryerson, T.: Ozone production in transpasific Asian pollution plumes and implications for ozone air quality in California, J. Geophys. Res., 109(D23), 910, https://doi.org/10.1029/2004JD004974, 2004. </mixed-citation>
</ref>
<ref id="ref16">
<label>16</label><mixed-citation publication-type="other" xlink:type="simple"> Huntrieser, H., Heland, J., Schlager, H., Forster, C., Stohl, A., Aufmhoff, H., Arnold, F., Scheel, H E., Campana, M., Gilge, S., Eixmann, R., and Cooper, O.: Intercontinental air pollution transport from North America to Europe: Experimental evidence from airborne measurements and surface observations, J. Geophys. Res., 110(D01), 305, https://doi.org/10.1029/2004JD005045, 2005. </mixed-citation>
</ref>
<ref id="ref17">
<label>17</label><mixed-citation publication-type="other" xlink:type="simple"> Jacob, D J., Logan, J., and Murti, P.: Effect of rising Asian emissions on surface ozone in the United States, Geophys. Res. Lett., 26, 2175-2178, 1999. </mixed-citation>
</ref>
<ref id="ref18">
<label>18</label><mixed-citation publication-type="other" xlink:type="simple"> Langmann, B., Bauer, S E., and Bey, I.: The influence of the global photochemical composition of the troposphere on European summer smog, Part I: Application of a global to mesoscale model chain, J. Geophys. Res., 108, 4146, https://doi.org/10.1029/2002JD002072, 2003. </mixed-citation>
</ref>
<ref id="ref19">
<label>19</label><mixed-citation publication-type="other" xlink:type="simple"> Li, Q., Jacob, D., Bey, I., Palmer, P., Duncan, B., Field, B., Martin, R., Fiore, A., Yantosca, R., Parrish, D., Simmonds, P., and Oltmans, S.: Transatlantic transport of pollution and its effects on surface ozone in Europe and North America, J. Geophys. Res., 107, 4166, https://doi.org/10.1029/2001JD001422, 2002. </mixed-citation>
</ref>
<ref id="ref20">
<label>20</label><mixed-citation publication-type="other" xlink:type="simple"> Li, Q., Jacob, D., Park, R., Wang, Y., Heald, C., Hudman, R., Yantosca, R., Martin, R., and Evans, M.: North American pollution outflow and the trapping of convectively lifted pollution by upper-level anticyclone, J. Geophys. Res., 110(D10), 301, https://doi.org/10.1029/2004JD005039, 2005. % </mixed-citation>
</ref>
<ref id="ref21">
<label>21</label><mixed-citation publication-type="other" xlink:type="simple">  </mixed-citation>
</ref>
<ref id="ref22">
<label>22</label><mixed-citation publication-type="other" xlink:type="simple"> Liu, H., Jacob, D., Bey, I., and Yantosca, R.: Constraints from 210Pb and 7Be on wet deposition and transport in a global three-dimensional chemical tracer model driven by assimilated meteorological fields, J. Geophys. Res., 106, 12 109, 12 109-12 128, 2001. </mixed-citation>
</ref>
<ref id="ref23">
<label>23</label><mixed-citation publication-type="other" xlink:type="simple"> Martin, R V., Chance, K., Jacob, D J., Kurosu, T P., Spurr, R. J D., Bucsela, E., Gleason, J F., Palmer, P I., Bey, I., Fiore, A M., Li, Q., Yantosca, R M., and Koelemeijer, R. B A.: An improved retrieval of tropospheric nitrogen dioxide from GOME, J. Geophys. Res., 107, 4437, https://doi.org/10.1029/2001JD001027, 2002. </mixed-citation>
</ref>
<ref id="ref24">
<label>24</label><mixed-citation publication-type="other" xlink:type="simple"> Martin, R V., Jacob, D., Yantosca, R., Chin, M., and Ginoux, P.: Global and Regional Decreases in Tropospheric Oxidants from Photochemical Effects of Aerosols, J. Geophys. Res., 108, 4097, https://doi.org/10.1029/2002JD002622, 2003. </mixed-citation>
</ref>
<ref id="ref25">
<label>25</label><mixed-citation publication-type="other" xlink:type="simple"> Park, R., Jacob, D J., Field, B D., Yantosca, R M., and Chin, M.: Natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosols in the United States: Implications for policy, J. Geophys. Res., 109, D15204, 10.1029/2003JD004473, 2004. </mixed-citation>
</ref>
<ref id="ref26">
<label>26</label><mixed-citation publication-type="other" xlink:type="simple"> Simon, P., Marenco, A., and Marenco, A.: Ozone Potential Vorticity correlations, Part IV , section II.6 of Measurement of Ozone and Water vapour by In-service Aircraft (MOZAIC), Final report to European Commission for contract ENV4-CT96-0321, 2000. </mixed-citation>
</ref>
<ref id="ref27">
<label>27</label><mixed-citation publication-type="other" xlink:type="simple"> Stohl, A.: A 1-year Lagrangian climatology of airstreams in the Northern Hemisphere troposphere and lowermost stratosphere, J. Geophys. Res., 106, 7263-7280, 2001. </mixed-citation>
</ref>
<ref id="ref28">
<label>28</label><mixed-citation publication-type="other" xlink:type="simple"> Stohl, A. and Trickl, T.: A textbook example of long-range transport: Simultaneous observation of ozone maxima of stratospheric and North American origin in the free troposphere over Europe, J. Geophys. Res., 104, 30 445-30 462, 1999. </mixed-citation>
</ref>
<ref id="ref29">
<label>29</label><mixed-citation publication-type="other" xlink:type="simple"> Stohl, A., Forster, C., Eckhardt, S., Spichtinger, N., Huntrieser, H., Heland, J., Schlager, H., Wilhelm, S., Arnold, F., and Cooper, O.: A backward modeling study of intercontinental pollution transport using aircraft measurements, J. Geophys. Res., 108, 4370, https://doi.org/10.1029/2002JD002862, 2003a. </mixed-citation>
</ref>
<ref id="ref30">
<label>30</label><mixed-citation publication-type="other" xlink:type="simple"> Stohl, A., Huntrieser, H., Richter, A., Beirle, S., Cooper, O., Eckhardt, S., Forster, C., James, P., Spichtinger, N., Wenig, M., Wagner, T., Burrows, J., and Platt, U.: Rapid intercontinental air pollution transport associated with a meteorological bomb, Atmos. Chem. Phys., 3, 969-985, 2003b. </mixed-citation>
</ref>
<ref id="ref31">
<label>31</label><mixed-citation publication-type="other" xlink:type="simple"> Stohl, A E.: Intercontinental Transport of Air Pollution, The Handbook of Environmental Chemistry, 4G, 325, 2004.   </mixed-citation>
</ref>
<ref id="ref32">
<label>32</label><mixed-citation publication-type="other" xlink:type="simple"> Thouret, V., Marenco, A., Logan, J., N\&apos;ed\&apos;elec, P., and Grouhel, C.: Comparisons of ozone measurements from the MOZAIC airborne program and the ozone sounding network at eight locations, J. Geophys. Res., 103, 25 695, 25 695-25 720, 1998. </mixed-citation>
</ref>
<ref id="ref33">
<label>33</label><mixed-citation publication-type="other" xlink:type="simple">Trickl, T., Cooper, O R., Eisele, H., James, P., Möcke, R., and Stohl, A.: Intercontinental transport and its influence on the ozone concentrations over central Europe: Three case studies, J. Geophys. Res., 108, 8530, https://doi.org/10.1029/2002JD002735, 2003.</mixed-citation>
</ref>
<ref id="ref34">
<label>34</label><mixed-citation publication-type="other" xlink:type="simple"> Wang, Y., Jacob, D., and Logan, J.: Global simulation of tropospheric ozone-NO$_\rm x$-Hydrocarbon chemistry, J. Geophys. Res., 103, 10 713-10 768, 1998. </mixed-citation>
</ref>
<ref id="ref35">
<label>35</label><mixed-citation publication-type="other" xlink:type="simple"> Wernli, H. and Davies, H C.: A Lagrangian-based analysis of extratropical cyclones. I: The method and some applications., Quart. J. Roy. Meteorol. Soc., 123, 467-489, 1997. </mixed-citation>
</ref>
<ref id="ref36">
<label>36</label><mixed-citation publication-type="other" xlink:type="simple"> Wesely, M.: Parameterization of surfaceresistance to gaseous dry deposition in regional-scale numerical models, Atmos. Environ., 23, 1293-1304, 1989. </mixed-citation>
</ref>
<ref id="ref37">
<label>37</label><mixed-citation publication-type="other" xlink:type="simple"> Wild, O. and Akimoto, H.: Intercontinental transport of ozone and its precursors in a three-dimensional global CTM, J. Geophys. Res., 106, 27 729, https://doi.org/10.1029/2000JD000123, 2001. </mixed-citation>
</ref>
<ref id="ref38">
<label>38</label><mixed-citation publication-type="other" xlink:type="simple"> Wild, O., Law, K S., McKenna, D S., Bandy, B J., Penkett, S A., and Pyle, J A.: Photochemical trajectory modeling studies of the North Atlantic region during August 1993, J. Geophys. Res., 101, 29 269, https://doi.org/10.1029/96JD00837, 1996. </mixed-citation>
</ref>
<ref id="ref39">
<label>39</label><mixed-citation publication-type="other" xlink:type="simple"> Wild, O., Zhu, Q., and Prather, M.: Fast-J: Accurate simulation of in- and below-cloud photolysis in global chemical models, J. Atmos. Chem., 37, 245-282, 2000. </mixed-citation>
</ref>
<ref id="ref40">
<label>40</label><mixed-citation publication-type="other" xlink:type="simple"> Zanis, P., Gerasopoulos, E., Priller, A., Schnabel, C., Stohl, A., Zerefos, C., Gaeggeler, H W., Tobler, L., Kubik, P W., Kanter, H J., Scheel, H E., Luterbacher, J., and Berger, M.: An estimate of the impact of stratosphere-to-troposphere transport (STT) on the lower free tropospheric ozone over the Alps using 10Be and 7Be measurements, J. Geophys. Res., 108, 8520, https://doi.org/10.1029/2002JD002604, 2003. </mixed-citation>
</ref>
<ref id="ref41">
<label>41</label><mixed-citation publication-type="other" xlink:type="simple"> Zellweger, C., Forrer, J., Hofer, P., Nyeki, S., Schwarzenbach, B., Weingarter, E., Ammann, M., and Baltensperger, U.: Partitioning of reactive nitrogen (NOy) and dependence on meteorological conditions in the free troposphere, Atmos. Chem. Phys., 2, 2259-2296, 2002. </mixed-citation>
</ref>
</ref-list>
</back>
</article>