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<article language="en">
	<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>10</volume_number>
		<issue_number>1</issue_number>
		<publication_year>2010</publication_year>
	</journal>
	<doi>10.5194/acpd-10-1417-2010</doi>
	<article_url>http://www.atmos-chem-phys-discuss.net/10/1417/2010/</article_url>
	<abstract_html>http://www.atmos-chem-phys-discuss.net/10/1417/2010/acpd-10-1417-2010.html</abstract_html>
	<fulltext_pdf>http://www.atmos-chem-phys-discuss.net/10/1417/2010/acpd-10-1417-2010.pdf</fulltext_pdf>
	<start_page>1417</start_page>
	<end_page>1456</end_page>
	<publication_date>2010-01-20</publication_date>
	<article_title content_type="html">Intercomparison methods for satellite measurements of atmospheric composition: application to tropospheric ozone from TES and OMI</article_title>
	<authors>
		<author numeration="1" affiliations="1">
			<name>L. Zhang</name>
			<email>linzhang@fas.harvard.edu</email>
		</author>
		<author numeration="2" affiliations="1,2">
			<name>D. J. Jacob</name>
		</author>
		<author numeration="3" affiliations="3,4,5">
			<name>X. Liu</name>
		</author>
		<author numeration="4" affiliations="2">
			<name>J. A. Logan</name>
		</author>
		<author numeration="5" affiliations="4">
			<name>K. Chance</name>
		</author>
		<author numeration="6" affiliations="6">
			<name>A. Eldering</name>
		</author>
		<author numeration="7" affiliations="7">
			<name>B. R. Bojkov</name>
		</author>
	</authors>
	<affiliations>
		<affiliation numeration="1" content_type="html">Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA</affiliation>
		<affiliation numeration="2" content_type="html">School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA</affiliation>
		<affiliation numeration="3" content_type="html">Goddard Earth Sciences and Technology Center, University of Maryland, Baltimore County, Baltimore, Maryland, USA</affiliation>
		<affiliation numeration="4" content_type="html">Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA</affiliation>
		<affiliation numeration="5" content_type="html">NASA Goddard Space Flight Center, Greenbelt, Maryland, USA</affiliation>
		<affiliation numeration="6" content_type="html">Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA</affiliation>
		<affiliation numeration="7" content_type="html">European Space Agency (ESA/ESRIN), Science, Applications and Future Technologies Department, Via Galileo Galilei, Casella Postale 64, 00044 Frascati (RM), Italy</affiliation>
	</affiliations>
	<abstract content_type="html">We analyze three different methods to validate and intercompare satellite
measurements of atmospheric composition, and apply them to tropospheric ozone
retrievals from the Tropospheric Emission Spectrometer (TES) and the Ozone
Monitoring Instrument (OMI). The first method (in situ method) uses in situ
vertical profiles for absolute instrument validation; it is limited by the
sparseness of in situ data. The second method (CTM method) uses a chemical
transport model (CTM) as an intercomparison platform; it provides a globally
complete intercomparison with relatively small noise added by model error.
The third method (averaging kernel smoothing method) involves smoothing the
retrieved profile from one instrument with the averaging kernel matrix of the
other; it also provides a global intercomparison but dampens the actual
difference between instruments and adds noise from the a priori. Application
to a full year (2006) of TES and OMI data shows mean positive biases of
5.3 parts per billion volume (ppbv) (10%) for TES and 2.8 ppbv (5%) for
OMI at 500 hPa relative to in situ data from ozonesondes. We show that the
CTM method (using the GEOS-Chem CTM) closely approximates results from the in
situ method while providing global coverage. It reveals that differences
between TES and OMI are generally less than 10 ppbv (18%), except at
northern mid-latitudes in summer and over tropical continents. The CTM method
allows for well-constrained CTM evaluation in places where the satellite
observations are consistent. We thus find that GEOS-Chem underestimates
tropospheric ozone in the tropics, reflecting a combination of possible
factors, and overestimates ozone in the northern subtropics and southern
mid-latitudes, likely because of excessive stratospheric influx.</abstract>
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</article>

