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	<journal>
		<journal_title>Atmospheric Chemistry and Physics</journal_title>
		<journal_url>www.atmos-chem-phys.net</journal_url>
		<issn>1680-7316</issn>
		<eissn>1680-7324</eissn>
		<volume_number>7</volume_number>
		<issue_number>3</issue_number>
		<publication_year>2007</publication_year>
	</journal>
	<doi>10.5194/acp-7-587-2007</doi>
	<article_url>http://www.atmos-chem-phys.net/7/587/2007/</article_url>
	<abstract_html>http://www.atmos-chem-phys.net/7/587/2007/acp-7-587-2007.html</abstract_html>
	<fulltext_pdf>http://www.atmos-chem-phys.net/7/587/2007/acp-7-587-2007.pdf</fulltext_pdf>
	<start_page>587</start_page>
	<end_page>598</end_page>
	<publication_date>2007-02-07</publication_date>
	<article_title content_type="html">Night-time radical chemistry during the NAMBLEX campaign</article_title>
	<authors>
		<author numeration="1" affiliations="1,6">
			<name>R. Sommariva</name>
		</author>
		<author numeration="2" affiliations="1">
			<name>M. J. Pilling</name>
			<email>m.j.pilling@leeds.ac.uk</email>
		</author>
		<author numeration="3" affiliations="1">
			<name>W. J. Bloss</name>
		</author>
		<author numeration="4" affiliations="1">
			<name>D. E. Heard</name>
		</author>
		<author numeration="5" affiliations="1,7">
			<name>J. D. Lee</name>
		</author>
		<author numeration="6" affiliations="2">
			<name>Z. L. Fleming</name>
		</author>
		<author numeration="7" affiliations="2">
			<name>P. S. Monks</name>
		</author>
		<author numeration="8" affiliations="3,8">
			<name>J. M. C. Plane</name>
		</author>
		<author numeration="9" affiliations="3,9">
			<name>A. Saiz-Lopez</name>
		</author>
		<author numeration="10" affiliations="4,10">
			<name>S. M. Ball</name>
		</author>
		<author numeration="11" affiliations="4">
			<name>M. Bitter</name>
		</author>
		<author numeration="12" affiliations="4">
			<name>R. L. Jones</name>
		</author>
		<author numeration="13" affiliations="3">
			<name>N. Brough</name>
		</author>
		<author numeration="14" affiliations="3">
			<name>S. A. Penkett</name>
		</author>
		<author numeration="15" affiliations="5">
			<name>J. R. Hopkins</name>
		</author>
		<author numeration="16" affiliations="5">
			<name>A. C. Lewis</name>
		</author>
		<author numeration="17" affiliations="1">
			<name>K. A. Read</name>
		</author>
	</authors>
	<affiliations>
		<affiliation numeration="1" content_type="html">School of Chemistry, University of Leeds, Leeds, UK</affiliation>
		<affiliation numeration="2" content_type="html">Department of Chemistry, University of Leicester, Leicester, UK</affiliation>
		<affiliation numeration="3" content_type="html">School of Environmental Sciences, University of East Anglia, Norwich, UK</affiliation>
		<affiliation numeration="4" content_type="html">University Chemical Laboratory, University of Cambridge, Cambridge, UK</affiliation>
		<affiliation numeration="5" content_type="html">Department of Chemistry, University of York, York, UK</affiliation>
		<affiliation numeration="6" content_type="html">now at: Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA</affiliation>
		<affiliation numeration="7" content_type="html">now at: Department of Chemistry, University of York, York, UK</affiliation>
		<affiliation numeration="8" content_type="html">now at: School of Chemistry, University of Leeds, Leeds, UK</affiliation>
		<affiliation numeration="9" content_type="html">now at: NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA</affiliation>
		<affiliation numeration="10" content_type="html">now at: Department of Chemistry, University of Leicester, Leicester, UK</affiliation>
	</affiliations>
	<abstract content_type="html">Night-time chemistry in the Marine Boundary Layer has been modelled
using a number of observationally constrained zero-dimensional
box-models. The models were based upon the Master Chemical Mechanism
(MCM) and the measurements were taken during the North Atlantic
Marine Boundary Layer Experiment (NAMBLEX) campaign at Mace Head,
Ireland in July&amp;ndash;September 2002.

&lt;br&gt;&lt;br&gt;

The model could reproduce, within the combined uncertainties, the
measured concentration of HO&lt;sub&gt;2&lt;/sub&gt; (within 30&amp;ndash;40%) during the
night 31 August&amp;ndash;1 September and of HO&lt;sub&gt;2&lt;/sub&gt;+RO&lt;sub&gt;2&lt;/sub&gt; (within
15&amp;ndash;30%) during several nights of the campaign. The model always
overestimated the NO&lt;sub&gt;3&lt;/sub&gt; measurements made by Differential
Optical Absorption Spectroscopy (DOAS) by up to an order of
magnitude or more, but agreed with the NO&lt;sub&gt;3&lt;/sub&gt; Cavity Ring-Down
Spectroscopy (CRDS) measurements to within 30&amp;ndash;50%. The most
likely explanation of the discrepancy between the two instruments
and the model is the reaction of the nitrate radical with
inhomogeneously distributed NO, which was measured at
concentrations of up to 10 ppt, even though this is not
enough to fully explain the difference between the DOAS measurements
and the model.

&lt;br&gt;&lt;br&gt;

A rate of production and destruction analysis showed that radicals
were generated during the night mainly by the reaction of ozone
with light alkenes. The cycling between HO&lt;sub&gt;2&lt;/sub&gt;/RO&lt;sub&gt;2&lt;/sub&gt;
and OH was maintained during the night by the low
concentrations of NO and the overall radical concentration
was limited by slow loss of peroxy radicals to form peroxides. A
strong peak in [NO&lt;sub&gt;2&lt;/sub&gt;] during the night 31 August&amp;ndash;1
September allowed an insight into the radical fluxes and the
connections between the HO&lt;sub&gt;x&lt;/sub&gt; and the NO&lt;sub&gt;3&lt;/sub&gt; cycles.</abstract>
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</article>

