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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>8</volume_number>
		<issue_number>4</issue_number>
		<publication_year>2008</publication_year>
	</journal>
	<doi>10.5194/acpd-8-15239-2008</doi>
	<article_url>http://www.atmos-chem-phys-discuss.net/8/15239/2008/</article_url>
	<abstract_html>http://www.atmos-chem-phys-discuss.net/8/15239/2008/acpd-8-15239-2008.html</abstract_html>
	<fulltext_pdf>http://www.atmos-chem-phys-discuss.net/8/15239/2008/acpd-8-15239-2008.pdf</fulltext_pdf>
	<start_page>15239</start_page>
	<end_page>15289</end_page>
	<publication_date>2008-08-12</publication_date>
	<article_title content_type="html">Hydroxyl radicals in the tropical troposphere over the Suriname rainforest: comparison of measurements with the box model MECCA</article_title>
	<authors>
		<author numeration="1" affiliations="1">
			<name>D. Kubistin</name>
			<email>kubistin@mpch-mainz.mpg.de</email>
		</author>
		<author numeration="2" affiliations="1">
			<name>H. Harder</name>
		</author>
		<author numeration="3" affiliations="1">
			<name>M. Martinez</name>
		</author>
		<author numeration="4" affiliations="1">
			<name>M. Rudolf</name>
		</author>
		<author numeration="5" affiliations="1">
			<name>R. Sander</name>
		</author>
		<author numeration="6" affiliations="1">
			<name>H. Bozem</name>
		</author>
		<author numeration="7" affiliations="1,3">
			<name>G. Eerdekens</name>
		</author>
		<author numeration="8" affiliations="1">
			<name>H. Fischer</name>
		</author>
		<author numeration="9" affiliations="1">
			<name>C. Gurk</name>
		</author>
		<author numeration="10" affiliations="1">
			<name>T. Klüpfel</name>
		</author>
		<author numeration="11" affiliations="1">
			<name>R. Königstedt</name>
		</author>
		<author numeration="12" affiliations="1">
			<name>U. Parchatka</name>
		</author>
		<author numeration="13" affiliations="2">
			<name>C. L. Schiller</name>
		</author>
		<author numeration="14" affiliations="1,4">
			<name>A. Stickler</name>
		</author>
		<author numeration="15" affiliations="1">
			<name>D. Taraborrelli</name>
		</author>
		<author numeration="16" affiliations="1">
			<name>J. Williams</name>
		</author>
		<author numeration="17" affiliations="1">
			<name>J. Lelieveld</name>
		</author>
	</authors>
	<affiliations>
		<affiliation numeration="1" content_type="html">Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz, Germany</affiliation>
		<affiliation numeration="2" content_type="html">Department of Chemistry, York University, Toronto, Canada</affiliation>
		<affiliation numeration="3" content_type="html">now at: Department of Biology, University of Antwerp, Belgium</affiliation>
		<affiliation numeration="4" content_type="html">now at: Institute for Atmospheric and Climate Science, ETH Zürich, Switzerland</affiliation>
	</affiliations>
	<abstract content_type="html">As a major source region of the hydroxyl radical OH, the Tropics
largely control the oxidation capacity of the atmosphere on a global scale.
However, emissions of hydrocarbons from the tropical rainforest that react
rapidly with OH can potentially deplete the amount of OH and thereby reduce
the oxidation capacity. The airborne GABRIEL field campaign in equatorial
South America (Suriname) in October 2005 investigated the influence of the
tropical rainforest on the HO&lt;sub&gt;x&lt;/sub&gt; budget (HO&lt;sub&gt;x&lt;/sub&gt;=OH+HO&lt;sub&gt;2&lt;/sub&gt;). 
The first observations of OH and HO&lt;sub&gt;2&lt;/sub&gt; over a tropical rainforest
are compared to steady state concentrations calculated with the atmospheric
chemistry box model MECCA. The important precursors and sinks for HO&lt;sub&gt;x&lt;/sub&gt;
chemistry, measured during the campaign, are used as constraining
parameters for the simulation of OH and HO&lt;sub&gt;2&lt;/sub&gt;. Significant
underestimations of HO&lt;sub&gt;x&lt;/sub&gt; are found by the model over land during the
afternoon, with mean ratios of observation to model of 12.2&amp;plusmn;3.5 and
4.1&amp;plusmn;1.4 for OH and HO&lt;sub&gt;2&lt;/sub&gt;, respectively. The discrepancy between
measurements and simulation results is correlated to the abundance of
isoprene. While for low isoprene mixing ratios (above ocean or at altitudes
&amp;gt;3 km), observation and simulation agree fairly well, for mixing ratios
&amp;gt;200 pptV (&amp;lt;3 km over the rainforest) the model tends to underestimate
the HO&lt;sub&gt;x&lt;/sub&gt; observations as a function of isoprene.

&lt;br&gt;&lt;br&gt;

Box model simulations have been performed with the condensed chemical
mechanism of MECCA and with the detailed isoprene reaction scheme of MCM,
resulting in similar results for HO&lt;sub&gt;x&lt;/sub&gt; concentrations. Simulations
with constrained HO&lt;sub&gt;2&lt;/sub&gt; concentrations show that the conversion from HO&lt;sub&gt;2&lt;/sub&gt;
to OH in the model is too low. However, by neglecting the isoprene chemistry
in the model, observations and simulations agree much better. An OH source
similar to the strength of the OH sink via isoprene chemistry is needed in
the model to resolve the discrepancy. A possible explanation is that the
oxidation of isoprene by OH not only dominates the removal of OH but also
produces it in a similar amount. Several additional reactions which directly
produce OH have been implemented into the box model, suggesting that upper
limits in producing OH are still not able to reproduce the observations
(improvement by factors of &amp;asymp;2.4 and &amp;asymp;2 for OH and HO&lt;sub&gt;2&lt;/sub&gt;,
respectively). We determine that OH has to be recycled to 94% instead of
the simulated 38% to match the observations, which is most likely to
happen in the isoprene degradation process, otherwise additional sources are
required.</abstract>
	<references>
		<reference numeration="1" content_type="text">   Atkinson, R., Baulch, D. L., Cox, R. A., Crowley, J. N., Hampson, R. F.,   Hynes, R. G., Jenkin, M. E., Rossi, M. J., and Troe, J.:   Evaluated kinetic and photochemical data for atmospheric chemistry:   Volume I – gas phase reactions of O&lt;sub&gt;x&lt;/sub&gt;, HO&lt;sub&gt;x&lt;/sub&gt;, NO&lt;sub&gt;x&lt;/sub&gt; and SO&lt;sub&gt;x&lt;/sub&gt; species, Atmos. Chem. Phys., 4, 1461–1738, 2004. </reference>
		<reference numeration="2" content_type="text">   Atkinson, R., Baulch, D. L., Cox, R. A., Crowley, J. N., Hampson, R. F.,   Hynes, R. G., Jenkin, M. E., Rossi, M. J., and Troe, J.:   Evaluated kinetic and photochemical data for atmospheric chemistry:   Volume II – reactions of organic species, Atmos. Chem. Phys., 6, 3625–4055, 2006. </reference>
		<reference numeration="3" content_type="text">   Butler, T. M., Taraborrelli, D., Brühl, C., Fischer, H., Harder, H.,   Martinez, M., Williams, J., Lawrence, M. G., and Lelieveld, J.:   Improved simulation of isoprene oxidation chemistry with the ECHAM5/MESSy   chemistry-climate model: lessons from the GABRIEL airborne field campaign, Atmos. Chem. Phys. Discuss., 8, 6273–6312, 2008.  </reference>
		<reference numeration="4" content_type="text">   Crawford, J., Davis, D., Olson, J., Chen, G., Liu, S., Gregory, G., Barrick, J., Sachse, G., Sandholm, S., Heikes, B., Singh, H., and Blake, D.:   Assessment of upper tropospheric HO&lt;sub&gt;x&lt;/sub&gt; source over the tropical Pacific based on NASA GTE/PEM data:   Net affect on HO&lt;sub&gt;x&lt;/sub&gt; and other photochemical parameters,   J. Geophys. Res., 104, 16 255–16 273, 1999.  </reference>
		<reference numeration="5" content_type="text">   Di Carlo, P., Brune, W. H., Martinez, M., Harder, H., Lesher, R., Ren, X.   Thornberry, T., Carroll, M. A., Young, V., Shepson, P. B., Riemer, D., Apel, E.   and Campbell, C.:   Missing OH Reactivity in a Forest: Evidence for Unknown Reactive Biogenic VOCs,   Science, 304, 722–725, 2004.  </reference>
		<reference numeration="6" content_type="text">   Dillon, T. J. and Crowley, J. N.:   Direct detection of OH formation in the reactions of HO&lt;sub&gt;2&lt;/sub&gt; with $\rm CH_3C(O)O_2$   and other substituted peroxy radicals, Atmos. Chem. Phys. Discuss., 8, 7111–7146, 2008. </reference>
		<reference numeration="7" content_type="text">   Eerdekens, G., Ganzeveld, L., Vilà-Guerau de Arellano, J.,   Klüpfel, T., Sinha, V., Yassaa, N., Williams, J., Harder, H., Kubistin, D., Martinez, M.,   and Lelieveld, J.:   Flux estimates of isoprene, methanol and acetone from airborne PTRMS measurements   over the tropical rainforest during the GABRIEL 2005 campaign,   Atmos. Chem. Phys. Discuss., 8, 12 903–12 969, 2008. </reference>
		<reference numeration="8" content_type="text">   Eisele, F. L., Mount, G. H., Fehsenfeld, F. C., Harder, J., Marovich, E.,   Parrish, D. D., Roberts, J., and Trainer, M.:   Intercomparison of tropospheric OH and ancillary trace gas measurements at Fritz Peak Observatory,   Colorado,   J. Geophys. Res., 99(18), 605–626, 1994.  </reference>
		<reference numeration="9" content_type="text">   Fehsenfeld, F., Calvert, J., Fall, R., Goldan, P., Guenther, A. B.,   Hewitt, C. N., Lamb, B., Liu, S., Trainer, M., Westberg, H., and Zimmermann, P.:   Emissions of volatile organic compounds from vegetation and the implications   for atmospheric chemistry,   Global Biogeochem. Cycles, 6, 389–430, 1992. </reference>
		<reference numeration="10" content_type="text">   Frost, G. J., Ellison, G. B., and Vaida, V.:   Organic Peroxyl Radical Photolysis in the Near-Infrared: Effects on Tropospheric   Chemistry,   J. Phys. Chem. A, 103, 10 169–10 178, 1999.  </reference>
		<reference numeration="11" content_type="text">   Fuentes, J. D., Lerdau, M., Atkinson, R., et al.:   Biogenic hydrocarbons in the atmospheric boundary layer: A review,   B. Am. Meteorol. Soc., 81(7),1537–1575, 2000. </reference>
		<reference numeration="12" content_type="text">   Ganzeveld, L., Eerdekens, G., Feig, G., Fischer, H., Harder, H.,   Königstedt, R., Kubistin, D., Martinez, M., Meixner, F., Scheeren, B.,   Williams, J., and Lelieveld, J.:   Surface and boundary layer exchanges of volatile organic compounds, nitrogen oxides and ozone   during the GABRIEL Campaign, Atmos. Chem. Phys. Discuss., 8, 11 909–11 965, 2008. \bibitem[Gierczak et al.(1997)] Gierczak1997   Gierczak, T., Burkholder, J. B., Talukdar, R. K., Mellouki, A., Barone, S. B.,   and Ravishankara, A. R.:   Atmospheric fate of methyl vinyl ketone and methacrolein,   J. Photochem. Photobiol. A: Chemistry, 110, 1–10, 1997.  \bibitem[Goldstein et al.(2004)] Goldstein2004   Goldstein, A. H., McKay, M., Kurpius, M. R., Schade, G. W., Lee, A., Holzinger, R.,   and Rasmussen, R. A.:   Forest thinning experiment confirms ozone deposition to forest canopy is dominated   by reaction with biogenic VOCs,   Geophys. Res. Lett., 31, L22106, doi:10.1029/2004GL021259, 2004.  </reference>
		<reference numeration="13" content_type="text">   Granier, C., Pétron, G., Müller, J.-F., and Brasseur, G.:   The impact of natural and anthropogenic hydrocarbons on the tropospheric budget of carbon monoxide,   Atmos. Environ., 34, 5255–5270, 2000.  </reference>
		<reference numeration="14" content_type="text">   Guenther, A. B., Hewitt, G. N., Erickson, D., et al.:   A global model of natural volatile organic compound emissions,   J. Geophys. Res., 100(D5), 8873–8892, 1995.  </reference>
		<reference numeration="15" content_type="text">   Hasson, A. S., Tyndall, G. S., and Orlando, J. J.:   A product yield study of the reaction of HO2 radicals with   Ethyl Peroxy ($\textC_2\textH_5\textO_2$),   Acetyl Peroxy ($\textCH_3\textC(O)O_2$),   and Acetonyl Peroxy ($\textCH_3\textC(O)CH_2\textO_2$) Radicals,   J. Phys. Chem. A, 108, 5979–5989, 2004. </reference>
		<reference numeration="16" content_type="text">   Heard, D. E. and Pilling, M. J.:   Measurement of OH and HO&lt;sub&gt;2&lt;/sub&gt; in the Troposphere,   Chem. Rev., 103, 5163–5198, 2003. </reference>
		<reference numeration="17" content_type="text">   Jackson, A. V. and Hewitt, C. N.:   Atmosphere Hydrogen Peroxide and Organic Hydorperoxides: A Review,   Crit. Rev. Environ. Sci. Technol., 29(2), 175–228, 1999.  </reference>
		<reference numeration="18" content_type="text">   Jenkin, M. E. and Hayman, G. D.:   Kinetics of Reactions of Primary, Secondary and Tertiary β-Hydroxy Peroxyl Radicals,   Application to Isoprene Degradation,   J. Chem. Soc. Faraday Trans., 91(13), 1911–1922, 1995.  </reference>
		<reference numeration="19" content_type="text">   Jenkin, M. E., Saunders, S. M., and Pilling, M. J.:   The tropospheric degradation of volatile organic compounds: a protocol for   mechanism development,   Atmos. Environ., 31, 81–104, 1997.  </reference>
		<reference numeration="20" content_type="text">   Jenkin, M. E., Hurley, M. D., and Wallington, T. J.:   Investigation of the radical product channel of the CH&lt;sub&gt;3&lt;/sub&gt;COO&lt;sub&gt;2&lt;/sub&gt;+HO&lt;sub&gt;2&lt;/sub&gt; reaction in the gas   phase,   Phys. Chem. Chem. Phys., 9, 3149–3162, 2007.  </reference>
		<reference numeration="21" content_type="text">   Jöckel, P., Tost, H., Pozzer, A., Brühl, C., Buchholz, J., Ganzeveld, L.,   Hoor, P., Kerkweg, A., Lawrence, M. G., Sander, R., Steil, B., Stiller, G., Tanarhte, M.,   Taraborrelli, D., van Aardenne, J., and Lelieveld, J.:   The atmospheric chemistry general circulation model ECHAM5/MESSy1:   consistent simulation of ozone from the surface to the mesosphere, Atmos. Chem. Phys., 6, 5067–5104, 2006. </reference>
		<reference numeration="22" content_type="text">   Karl., T., Guenther, A., Yokelson, R. J., Greenberg, J., Potosnak, M.,   Blake, D. R., and Artaxo, P.:   The tropical forest and fire emissions experiment: Emission, chemistry and transport of   biogenic volatile organic compounds in the lower atmosphere over Amazonia,   J. Geophys. Res., 112, D18302, doi:10.1029/2007JD008539, 2007. </reference>
		<reference numeration="23" content_type="text">   Kesselmeier, J. and Staudt, M.:   Biogenic volatile organic compounds (VOC): An overview on emission, physiology and ecology,   J. Atmos. Chem., 33, 23–88, 1999.  </reference>
		<reference numeration="24" content_type="text">   Von Kuhlmann, R., Lawrence, M. G., Pöschl, U., and Crutzen, P. J.:   Sensitivities in global scale modelling of isoprene, Atmos. Chem. Phys. 4, 1–17, 2004. </reference>
		<reference numeration="25" content_type="text">   Kuhn, U., Andreae, M. O., Ammann, C., Araújo, A. C., Brancaleoni, E.,   Ciccioli, P., Dindorf, T., Frattoni, M., Gatti, L. V., Ganzeveld, L., Kruijt, B.,   Lelieveld, J., Lloyd, J., Meixner, F. X., Nobre, A. D., Pöschl, U., Spirig, C.,   Stefani, P., Thielmann, A., Valentini, R., and Kesselmeier, J.:   Isoprene and monoterpene fluxes from Central Amazonian rainforest inferred from tower-based and   airborne measurements, and implications on the atmospheric chemistry and the local carbon budget,   Atmos. Chem. Phys., 7, 2855–2879, 2007. </reference>
		<reference numeration="26" content_type="text">   Lelieveld, J., Peters, V., Dentener, F. J., and Krol, M.:   Stability of tropospheric hydroxyl chemistry,   J. Geophys. Res., 107, D23, doi:10.1029/2002JD002272, 2002.  </reference>
		<reference numeration="27" content_type="text">   Lelieveld, J., Butler, T. M., Crowley, J., Dillon, T., Fischer, H., Ganzeveld, L.,   Harder, H., Lawrence, M. G., Martinez, M., Taraborrelli, D., and Williams, J.:   Atmospheric oxidation capacity sustained by a tropical forest,   Nature, 452, 737–740, 2008. </reference>
		<reference numeration="28" content_type="text">   Levy II, H.:   Normal atmosphere: Large radical and formaldehyde concentrations predicted,   Science, 173, 141–143, 1971. </reference>
		<reference numeration="29" content_type="text">   Logan, J. A., Prather, M. J., Wofsy, S. C., and McElroy, M. B.:   Tropospheric chemistry: A global perspective,   J. Geophys. Res., 86, 7210–7254, 1981.  </reference>
		<reference numeration="30" content_type="text">   Madronich, S. and Flocke, S.:   The role of solar radiation in atmospheric chemistry,   in: Handbook of Environmental Chemistry, edited by: Boule, P., pp. 1–26, Springer, New York, 1998. </reference>
		<reference numeration="31" content_type="text">   Martinez, M., Harder, H., Kubistin, D., Rudolf, M., Bozem, H., Eerdekens, G.,   Fischer, H., Gurk, C., Königsstedt, R., Klüpfel, T., Parchatka, U.,   Schiller, C. L., Stickler, A., Williams, J., and Lelieveld, J.:   Hydroxyl radicals in the tropical troposphere over the Suriname rainforest: airborne measurements,   Atmos. Chem. Phys. Discuss., accepted, 2008.   %acpd-2008-0372  </reference>
		<reference numeration="32" content_type="text">   Paulson, S. E., Flagan, R. C., and Seinfeld, J. H.:   Atmospheric photo-oxidation of isoprene: part I: the hydroxyl radical and ground state atomic   oxygen reactions,   Int. J. Chem. Kin., 24, 79–101, 1992. </reference>
		<reference numeration="33" content_type="text">   Pinho, P. G., Pio, C. A., and Jenkin, M. E.:   Evaluation of isoprene degradation in the detailed tropospheric chemical mechanism, MCM v3,   using environmental chamber data,   Atmos. Environ., 39, 1303–1322, 2005. </reference>
		<reference numeration="34" content_type="text">   Pöschl, U., Von Kuhlmann, R., Poisson, N., and Crutzen, P. J.:   Development and intercomparison of condensed isoprene oxidation mechanisms for   global atmospheric modeling,   J. Atmos. Chem., 37, 29–52, 2000. \bibitem[Poisson et al.(2000)] Poisson2000   Poisson, N., Kanakidou, M., and Crutzen, P. J.:   Impact of Non-Methane Hydrocarbons on Tropospheric Chemistry and the Oxidizing Power of   the Gobal Troposphere: 3-Dimensional Modelling Results,   J. Atmos. Chem., 36, 157–230, 2000. </reference>
		<reference numeration="35" content_type="text">   Ren, X., Olson, J. R., Crawford, J. H., Brune, W. H., Mao, J., Long, R. B., Chen, Z.,   Chen, G., Avery, M. A., Sachse, G. W., Barrick, J. D., Diskin, G. S., Huey, L. G.,   Fried, A., Cohen, R. C., Heikes, B., Wennberg, P.,Singh, H. B., Blake, D. R., and Shetter, R. E.:   HO&lt;sub&gt;x&lt;/sub&gt; chemistry during INTEX-A 2004:   Observation, model calculation, and comparison with previous studies,   J. Geophys. Res., 113, D05310, doi:10.1029/2007JD009166, 2008. </reference>
		<reference numeration="36" content_type="text">   Sander, R., Kerkweg, A., Jöckel, P., and Lelieveld, J.:   Technical note: The new comprehensive atmospheric chemistry module MECCA, Atmos. Chem. Phys., 5, 445–450, 2005.  </reference>
		<reference numeration="37" content_type="text">   Sander, S. P., Friedl, R. R., Golden, D. M., Kurylo, M. J., Moortgat, G. K., Wine, P. H.,   Ravishankara, A. R., Kolb, C. E., Molina, M. J., Finlayson-Pitts, B. J., Huie, R. E., and Orkin, V. L.:   Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies,   Evalutation Number 15, JPL Publication 06-2,   NASA Jet Propulsion Laboratory, Pasadena, California, 2006.  </reference>
		<reference numeration="38" content_type="text">   Saunders, S. M., Jenkin, M. E., Derwent, R. G., and Pilling, M. J.:   World wide web site of a master chemical mechanism (MCM) for use in tropospheric chemistry models,   available at: http://www.chem.leeds.ac.uk/Atmospheric/MCM,   Atmos. Environ., 31, 1249, 1997. </reference>
		<reference numeration="39" content_type="text">   Saunders, S. M., Jenkin, M. E., Derwent, R. G., and Pilling, M. J.:   Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part A):   tropospheric degradation of non-aromatic volatile organic compounds,   Atmos. Chem. Phys., 3, 161–180, 2003. </reference>
		<reference numeration="40" content_type="text">   Schmidt, U.: Molecular hydrogen in the atmosphere,   Tellus, 26, 78–90, 1974. </reference>
		<reference numeration="41" content_type="text">   Schmidt, U.:   The latitudinal and vertical distribution of molecular hydrogen in the troposphere,   J. Geophys. Res., 83, 941–946,1978.  </reference>
		<reference numeration="42" content_type="text">       Stickler A., Fischer, H., Bozem, H., Gurk, C., Schiller, C., Martinez-Harder, M.,       Kubistin, D., Harder, H., Williams, J., Eerdekens, G., Yassaa, N., Ganzeveld, L., Sander, R.,      and Lelieveld, J.:   Chemistry, transport and dry deposition of trace gases in the boundary layer over the   tropical Atlantic Ocean and the Guyanas during the GABRIEL field campaign, Atmos. Chem. Phys., 7, 3933–3956, 2007.  </reference>
		<reference numeration="43" content_type="text">   Tan., D., Faloona, I., Simpas, J. B., Brune, W., Shepson, P. B., Couch, T. L.,   Summer, A. L., Carroll, M. A., Thornberry, T., Apel, E., Riemer, D., and Stockwell, W.:   HO&lt;sub&gt;x&lt;/sub&gt; budgets in a deciduous forest: Results from the PROPHET summer 1998 campaign,   J. Geophys. Res., 106, 24 407–24 427, 2001.  </reference>
		<reference numeration="44" content_type="text">   Vaghjiani, G. L. and Ravishankara, A. R.:   Absorption cross sections of CH&lt;sub&gt;3&lt;/sub&gt;OOH, $\rm H_2O_2$ and $\rm D_2O_2$ vapors between   210 nm and 365 nm at 297 K,   J. Geophys. Res., 94, 3487–3492, 1989. \bibitem[Wang et al.(1998)] Wang1998   Wang, Y., Jacob, D. J., and Logan, J. A.:   Global simulations of tropospheric O&lt;sub&gt;3&lt;/sub&gt; – NO&lt;sub&gt;x&lt;/sub&gt; – hydrocarbon chemistry. 3 Origin of   tropospheric ozone   effects of non-methane hydrocarbons,   J. Geophys. Res., 103, 10 757–10 767, 1998.  \bibitem[Warneke et al.(2001)] Warneke2001   Warneke, C., Holzinger, R., Hansel, A., Jordan, A., Lindinger, W.,   Pöschl, U., Williams, J., Hoor, P., Fischer, H., Crutzen, P. J.,   Scheeren, H. A., and Lelieveld, J.:   Isoprene and Its Oxidation Products Methyl Vinyl Ketone, Methacrolein,   and Isoprene Related Peroxides Measured Online over the Tropical Rain Forest   of Suriname in March 1998,   J. Atmos. Chem., 38, 167–185, 2001.  \bibitem[Williams et al.(2007)] Williams2007   Williams, J., Yassaa, N., Bartenbach, S., and Lelieveld, J.:   Mirror image hydrocarbons from Tropical and Boreal forests,   Atmos. Chem. Phys., 7, 973–980, 2007.  </reference>
		<reference numeration="45" content_type="text">   Zimmermann, P. R., Greenberg, J. P., and Westberg, C. E.:   Measurements of atmospheric hydrocarbons and biogenic emission fluxes   in the Amazon boundary layer,   J. Geophys. Res., 93, 1407–1416, 1988.  </reference>
	</references>
</article>

