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	<journal>
		<journal_title>Atmospheric Chemistry and Physics Discussions</journal_title>
		<journal_url>www.atmos-chem-phys-discuss.net</journal_url>
		<issn>1680-7367</issn>
		<eissn>1680-7375</eissn>
		<volume_number>9</volume_number>
		<issue_number>1</issue_number>
		<publication_year>2009</publication_year>
	</journal>
	<doi>10.5194/acpd-9-411-2009</doi>
	<article_url>http://www.atmos-chem-phys-discuss.net/9/411/2009/</article_url>
	<abstract_html>http://www.atmos-chem-phys-discuss.net/9/411/2009/acpd-9-411-2009.html</abstract_html>
	<fulltext_pdf>http://www.atmos-chem-phys-discuss.net/9/411/2009/acpd-9-411-2009.pdf</fulltext_pdf>
	<start_page>411</start_page>
	<end_page>462</end_page>
	<publication_date>2009-01-07</publication_date>
	<article_title content_type="html">Technical Note: Feasibility of CO&lt;sub&gt;2&lt;/sub&gt; profile retrieval from limb viewing solar occultation made by the ACE-FTS instrument</article_title>
	<authors>
		<author numeration="1" affiliations="1">
			<name>P. Y. Foucher</name>
			<email>pierre-yves.foucher@lmd.polytechnique.fr</email>
		</author>
		<author numeration="2" affiliations="1">
			<name>A. Chédin</name>
		</author>
		<author numeration="3" affiliations="2">
			<name>G. Dufour</name>
		</author>
		<author numeration="4" affiliations="1">
			<name>V. Capelle</name>
		</author>
		<author numeration="5" affiliations="3">
			<name>C. D. Boone</name>
		</author>
		<author numeration="6" affiliations="3,4">
			<name>P. Bernath</name>
		</author>
	</authors>
	<affiliations>
		<affiliation numeration="1" content_type="html">Laboratoire de Météorologie Dynamique/Institut Pierre Simon  Laplace, Ecole Polytechnique, 91128 Palaiseau,  France</affiliation>
		<affiliation numeration="2" content_type="html">Laboratoire Inter-universitaire des Systèmes Atmosphériques,  Faculté des Sciences et Technologies, 61 avenue du Général de Gaulle,  94010 Créteil, France</affiliation>
		<affiliation numeration="3" content_type="html">Department of Chemistry, University of Waterloo, Ontario, N2L3G1, Canada</affiliation>
		<affiliation numeration="4" content_type="html">Department of Chemistry, University of York, Heslington, York, UK.YO105DD, UK</affiliation>
	</affiliations>
	<abstract content_type="html">Major limitations of our present knowledge of the global distribution
      of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere are the uncertainty in atmospheric
      transport mixing and the sparseness of in situ concentration
      measurements. Limb viewing space-borne sounders, observing the
      atmosphere along tangential optical paths, offer a vertical resolution
      of a few kilometres for profiles, which is much better than currently
      flying or planned nadir sounding instruments can achieve. In this
      paper, we analyse the feasibility of obtaining CO&lt;sub&gt;2&lt;/sub&gt; vertical
      profiles in the 5–25 km altitude range from the Atmospheric
      Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS, launched
      in August 2003), high spectral resolution solar occultation
      measurements. Two main difficulties must be overcome: (i) the accurate
      determination of the instrument pointing parameters (tangent heights)
      and pressure/temperature profiles independently from an a priori
      CO&lt;sub&gt;2&lt;/sub&gt; profile, and (ii) the potential impact of uncertainties in
      the temperature knowledge on the retrieved CO&lt;sub&gt;2&lt;/sub&gt; profile. The
      first difficulty has been solved using the N&lt;sub&gt;2&lt;/sub&gt;
      collision-induced continuum absorption near 4 μm to determine
      tangent heights, pressure and temperature from the ACE-FTS
      spectra. The second difficulty has been solved by a careful selection
      of CO&lt;sub&gt;2&lt;/sub&gt; spectral micro-windows. Retrievals using synthetic
      spectra made under realistic simulation conditions show a vertical
      resolution close to 2.5 km and accuracy of the order of
      2 ppm after averaging over 25 profiles. These results open the
      way to promising studies of transport mechanisms and carbon fluxes
      from the ACE-FTS measurements.</abstract>
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