References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-11-10565-2011

First direct measurements of formaldehyde flux via eddy covariance: implications for missing in-canopy formaldehyde sources

DiGangi

J. P.

¹ Boyle

E. S.

¹ Karl

² Harley

² Turnipseed

² Kim

² Cantrell

² Maudlin III

R. L.

² ³ ⁷ Zheng

² Flocke

² Hall

S. R.

² Ullmann

² Nakashima

⁶ Paul

J. B.

⁴ Wolfe

G. M.

¹ Desai

A. R.

⁵ Kajii

⁶ Guenther

² Keutsch

F. N.

Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA

Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO, USA

Department of Physics, University of Helsinki, Finland

Thermo Fisher Scientific, Redwood City, CA, USA

Department of Atmospheric & Oceanic Sciences, University of Wisconsin-Madison, Madison, WI, USA

Division of Applied Chemistry, Faculty of Urban Environmental Sciences, Tokyo Metropolitan University, Japan

now at: Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO, USA

26 10 2011

11 20 10565 10578

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This article is available from http://www.atmos-chem-phys.net/11/10565/2011/acp-11-10565-2011.html

The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/10565/2011/acp-11-10565-2011.pdf

We report the first observations of formaldehyde (HCHO) flux measured via eddy covariance, as well as HCHO concentrations and gradients, as observed by the Madison Fiber Laser-Induced Fluorescence Instrument during the BEACHON-ROCS 2010 campaign in a rural, Ponderosa Pine forest northwest of Colorado Springs, CO. A median noon upward flux of ~80 μg m−2 h−1 (~24 pptv m s−1) was observed with a noon range of 37 to 131 μg m−2 h−1. Enclosure experiments were performed to determine the HCHO branch (3.5 μg m-2 h−1) and soil (7.3 μg m−2 h−1) direct emission rates in the canopy. A zero-dimensional canopy box model, used to determine the apportionment of HCHO source and sink contributions to the flux, underpredicted the observed HCHO flux by a factor of 6. Simulated increases in concentrations of species similar to monoterpenes resulted in poor agreement with measurements, while simulated increases in direct HCHO emissions and/or concentrations of species similar to 2-methyl-3-buten-2-ol best improved model/measurement agreement. Given the typical diurnal variability of these BVOC emissions and direct HCHO emissions, this suggests that the source of the missing flux is a process with both a strong temperature and radiation dependence.

References 1

Atkinson, R. and Arey, J.: Gas-phase tropospheric chemistry of biogenic volatile organic compounds: a review, Atmos. Environ. , 37, S197–S219, http://dx.doi.org/10.1016/S1352-2310(03)00391-1doi:10.1016/S1352-2310(03)00391-1, 2003.

Atkinson, R., Baulch, D. L., Cox, R. A., Crowley, J. N., Hampson, R. F., Hynes, R. G., Jenkin, M. E., Rossi, M. J., Troe, J., and IUPAC Subcommittee: Evaluated kinetic and photochemical data for atmospheric chemistry: Volume II - gas phase reactions of organic species, Atmos. Chem. Phys., 6, 3625–4055, http://dx.doi.org/10.5194/acp-6-3625-2006doi:10.5194/acp-6-3625-2006, 2006.

Baker, B., Guenther, A., Greenberg, J., Goldstein, A., and Fall, R.: Canopy fluxes of 2-methyl-3-buten-2-ol over a ponderosa pine forest by relaxed eddy accumulation: Field data and model comparison, J. Geophys. Res.-Atmos., 104, 26 107–26 114, 1999.

Baldocchi, D D., Hicks, B B., and Meyers, T P.: Measuring Biosphere-Atmosphere Exchanges of Biologically Related Gases with Micrometeorological Methods, Ecology, 69, 1331–1340, 1988.

Berger, B W., Davis, K J., Yi, C X., Bakwin, P S., and Zhao, C L.: Long-term carbon dioxide fluxes from a very tall tower in a northern forest: Flux measurement methodology, J. Atmos. Ocean Tech., 18, 529–542, 2001.

Carrasco, N., Doussin, J F., O'Connor, M., Wenger, J C., Picquet-Varrault, B., Durand-Jolibois, R., and Carlier, P.: Simulation chamber studies of the atmospheric oxidation of 2-methyl-3-buten-2-ol: Reaction with hydroxyl radicals and ozone under a variety of conditions, J. Atmos. Chem., 56, 33–55, http://dx.doi.org/10.1007/s10874-006-9041-ydoi:10.1007/s10874-006-9041-y, 2007.

Choi, W., Faloona, I. C., Bouvier-Brown, N. C., McKay, M., Goldstein, A. H., Mao, J., Brune, W. H., LaFranchi, B. W., Cohen, R. C., Wolfe, G. M., Thornton, J. A., Sonnenfroh, D. M., and Millet, D. B.: Observations of elevated formaldehyde over a forest canopy suggest missing sources from rapid oxidation of arboreal hydrocarbons, Atmos. Chem. Phys., 10, 8761–8781, http://dx.doi.org/10.5194/acp-10-8761-2010doi:10.5194/acp-10-8761-2010, 2010.

Cojocariu, C., Kreuzwieser, J., and Rennenberg, H.: Correlation of short-chained carbonyls emitted from Picea abies with physiological and environmental parameters, New Phytol., 162, 717–727, http://dx.doi.org/10.1111/j.1469-8137.2004.01061.xdoi:10.1111/j.1469-8137.2004.01061.x, 2004.

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, http://dx.doi.org/10.1126/science.1094392doi:10.1126/science.1094392, 2004.

%Dillon, T J. and Crowley, J N.: Direct detection of OH formation in the % reactions of \chemHO_2 with \chemCH_3C(O)O_2 and other substituted % peroxy radicals, Atmospheric Chemistry and Physics, 8, 4877–4889, 2008. Dillon, T. J. and Crowley, J. N.: Direct detection of OH formation in the reactions of \chemHO_2 with \chemCH_3C(O)O_2 and other substituted peroxy radicals, Atmos. Chem. Phys., 8, 4877–4889, http://dx.doi.org/10.5194/acp-8-4877-2008doi:10.5194/acp-8-4877-2008, 2008.

%Farmer, D K., Wooldridge, P J., and Cohen, R C.: Application of % thermal-dissociation laser induced fluorescence (TD-LIF) to measurement of % \chemHNO_3, $§igma$alkyl nitrates, $§igma$peroxy nitrates, and % \chemNO_2 fluxes using eddy covariance, Atmospheric Chemistry and % Physics, 6, 3471–3486, 2006. Farmer, D. K., Wooldridge, P. J., and Cohen, R. C.: Application of thermal-dissociation laser induced fluorescence (TD-LIF) to measurement of HNO3, $§igma$alkyl nitrates, $§igma$peroxy nitrates, and \chemNO_2 fluxes using eddy covariance, Atmos. Chem. Phys., 6, 3471–3486, http://dx.doi.org/10.5194/acp-6-3471-2006doi:10.5194/acp-6-3471-2006, 2006.

Foken, T. and Wichura, B.: Tools for quality assessment of surface-based flux measurements, Agr. Forest Meteorol., 78, 83–105, 1996.

Fried, A., McKeen, S., Sewell, S., Harder, J., Henry, B., Goldan, P., Kuster, W., Williams, E., Baumann, K., Shetter, R., and Cantrell, C.: Photochemistry of formaldehyde during the 1993 Tropospheric OH Photochemistry Experiment, J. Geophys. Res.-Atmos., 102, 6283–6296, 1997.

Ganzeveld, L., Eerdekens, G., Feig, G., Fischer, H., Harder, H., K�nigstedt, R., Kubistin, D., Martinez, M., Meixner, F. X., Scheeren, H. A., Sinha, V., Taraborrelli, D., Williams, J., Vil�-Guerau de Arellano, J., and Lelieveld, J.: Surface and boundary layer exchanges of volatile organic compounds, nitrogen oxides and ozone during the GABRIEL campaign, Atmos. Chem. Phys., 8, 6223–6243, http://dx.doi.org/10.5194/acp-8-6223-2008doi:10.5194/acp-8-6223-2008, 2008.

Galloway, M. M., DiGangi, J. P., Hottle, J. R., Huisman, A. J., Mielke, L. H., Alaghmand, M., Shepson, P. B., Weremijewicz, J., Klavon, H., McNeal, F. M., Carroll, M. A., Griffith, S., Hansen, R. F., Stevens, P. S., Bertman, S. B., and Keutsch, F. N.: Observations and modeling of formaldehyde at the prophet mixed hardwood forest site in 2008, Atmos. Environ., accepted, http://dx.doi.org/10.1016/j.atmosenv.2011.09.053doi:10.1016/j.atmosenv.2011.09.053, 2011.

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, L22 106, http://dx.doi.org/10.1029/2004gl021259doi:10.1029/2004gl021259, 2004.

Hansel, A., Jordan, A., Warneke, C., Holzinger, R., and Lindinger, W.: Improved detection limit of the proton-transfer reaction mass spectrometer: on-line monitoring of volatile organic compounds at mixing ratios of a few \unitppt_v, Rapid Commun. Mass Sp., 12, 871–875, http://dx.doi.org/10.1002/(SICI)1097-0231(19980715)12:13<871::AID-RCM245>3.0.CO;2-Ldoi:10.1002/(SICI)1097-0231(19980715)12:13<871::AID-RCM245>3.0.CO;2-L, 1998.

Hasson, A S., Tyndall, G S., and Orlando, J J.: A product yield study of the reaction of \chemHO_2 radicals with ethyl peroxy (\chemC_2H_5O_2), acetyl peroxy (\chemCH_3C(O)O_2), and acetonyl peroxy (\chemCH_3C(O)CH_2O_2) radicals, J. Phys. Chem. A, 108, 5979–5989, http://dx.doi.org/10.1021/Jp048873tdoi:10.1021/Jp048873t, 2004.

Hofzumahaus, A., Rohrer, F., Lu, K., Bohn, B., Brauers, T., Chang, C., Fuchs, H., Holland, F., Kita, K., Kondo, Y., Li, X., Lou, S., Shao, M., Zeng, L., Wahner, A., and Zhang, Y.: Amplified Trace Gas Removal in the Troposphere, Science, 324, 1702–1704, http://dx.doi.org/10.1126/science.1164566doi:10.1126/science.1164566, 2009.

Holzinger, R., Lee, A., Paw, K. T., and Goldstein, U. A. H.: Observations of oxidation products above a forest imply biogenic emissions of very reactive compounds, Atmos. Chem. Phys., 5, 67–75, http://dx.doi.org/10.5194/acp-5-67-2005doi:10.5194/acp-5-67-2005, 2005.

Hornbrook, R. S., Crawford, J. H., Edwards, G. D., Goyea, O., Mauldin III, R. L., Olson, J. S., and Cantrell, C. A.: Measurements of tropospheric HO2 and RO2 by oxygen dilution modulation and chemical ionization mass spectrometry, Atmos. Meas. Tech., 4, 735–756, http://dx.doi.org/10.5194/amt-4-735-2011doi:10.5194/amt-4-735-2011, 2011.

Hottle, J R., Huisman, A J., Digangi, J P., Kammrath, A., Galloway, M M., Coens, K L., and Keutsch, F N.: A Laser Induced Fluorescence-Based Instrument for In-Situ Measurements of Atmospheric Formaldehyde, Environ. Sci. Technol., 43, 790–795, http://dx.doi.org/10.1021/Es801621fdoi:10.1021/Es801621f, 2009. %

%Hottle, J R., Galloway, M M., DiGangi, J P., Huisman, A J., Mielke, %L H., % Alaghmand, M., Shepson, P B., Weremijewicz, J., Klavon, H., McNeal, F M., % Carroll, M A., Griffith, S., Hansen, R F., Stevens, P S., Bertman, S B., % and Keutsch, F N.: Observations and Modeling of HCHO at the PROPHET Mixed % Hardwood Forest Site in 2008, Atmos. Environ., submitted\blackbox\textbfupdate?, 2011.

Hutterli, M A., McConnell, J R., Chen, G., Bales, R C., Davis, D D., and Lenschow, D H.: Formaldehyde and hydrogen peroxide in air, snow and interstitial air at South Pole, Atmos. Environ., 38, 5439–5450, http://dx.doi.org/10.1016/j.atmosenv.2004.06.003doi:10.1016/j.atmosenv.2004.06.003, 2004.

Jacobi, H W., Frey, M M., Hutterli, M A., Bales, R C., Schrems, O., Cullen, N J., Steffen, K., and Koehler, C.: Measurements of hydrogen peroxide and formaldehyde exchange between the atmosphere and surface snow at Summit, Greenland, Atmos. Environ., 36, 2619–2628, 2002.

Jenkin, M E., Hurley, M D., and Wallington, T J.: Investigation of the radical product channel of the \chemCH_3C(O)O_2+HO_2 reaction in the gas phase, Phys. Chem. Chem. Phys., 9, 3149–3162, http://dx.doi.org/10.1039/B702757edoi:10.1039/B702757e, 2007.

Jensen, N O. and Hummelshoj, P.: Derivation of Canopy Resistance for Water-Vapor Fluxes over a Spruce Forest, Using a New Technique for the Viscous Sublayer Resistance, Agr. Forest. Meteorol., 73, 339–352, 1995.

Jensen, N O. and Hummelshoj, P.: Erratum to "Derivation of canopy resistance for water vapor fluxes over a spruce forest, using a new technique for the viscous sublayer resistance", Agr. Forest. Meteorol., 85, 289–289, 1997.

Jimenez, J L., Canagaratna, M R., Donahue, N M., Prevot, A. S H., Zhang, Q., Kroll, J H., DeCarlo, P F., Allan, J D., Coe, H., Ng, N L., Aiken, A C., Docherty, K S., Ulbrich, I M., Grieshop, A P., Robinson, A L., Duplissy, J., Smith, J D., Wilson, K R., Lanz, V A., Hueglin, C., Sun, Y L., Tian, J., Laaksonen, A., Raatikainen, T., Rautiainen, J., Vaattovaara, P., Ehn, M., Kulmala, M., Tomlinson, J M., Collins, D R., Cubison, M J., Dunlea, E J., Huffman, J A., Onasch, T B., Alfarra, M R., Williams, P I., Bower, K., Kondo, Y., Schneider, J., Drewnick, F., Borrmann, S., Weimer, S., Demerjian, K., Salcedo, D., Cottrell, L., Griffin, R., Takami, A., Miyoshi, T., Hatakeyama, S., Shimono, A., Sun, J Y., Zhang, Y M., Dzepina, K., Kimmel, J R., Sueper, D., Jayne, J T., Herndon, S C., Trimborn, A M., Williams, L R., Wood, E C., Middlebrook, A M., Kolb, C E., Baltensperger, U., and Worsnop, D R.: Evolution of Organic Aerosols in the Atmosphere, Science, 326, 1525–1529, http://dx.doi.org/10.1126/science.1180353doi:10.1126/science.1180353, 2009.

Junkermann, W., Platt, U., and Volzthomas, A.: A Photoelectric Detector for the Measurement of Photolysis Frequencies of Ozone and Other Atmospheric Molecules, J. Atmos. Chem., 8, 203–227, 1989.

Kaimal, J C. and Finnigan, J J.: Atmospheric Boundary Layer Flows - Their Structure and Measurement, Oxford University Press, New York, USA, 1994.

Kanemasu, E T., Powers, W L., and Sij, J W.: Field Chamber Measurements of \chemCO_2 Flux from Soil Surface, Soil Science, 118, 233–237, 1974.

Karl, T., Guenther, A., Turnipseed, A., Tyndall, G., Artaxo, P., and Martin, S.: Rapid formation of isoprene photo-oxidation products observed in Amazonia, Atmos. Chem. Phys., 9, 7753–7767, http://dx.doi.org/10.5194/acp-9-7753-2009doi:10.5194/acp-9-7753-2009, 2009.

Kesselmeier, J., Bode, K., Hofmann, U., Müller, H., Schafer, L., Wolf, A., Ciccioli, P., Brancaleoni, E., Cecinato, A., Frattoni, M., Foster, P., Ferrari, C., Jacob, V., Fugit, J L., Dutaur, L., Simon, V., and Torres, L.: Emission of short chained organic acids, aldehydes and monoterpenes from \textitQuercus ilex L. and \textitPinus pinea L. in relation to physiological activities, carbon budget and emission algorithms, Atmos. Environ., 31, 119–133, 1997.

Kim, S., Karl, T., Guenther, A., Tyndall, G., Orlando, J., Harley, P., Rasmussen, R., and Apel, E.: Emissions and ambient distributions of Biogenic Volatile Organic Compounds (BVOC) in a ponderosa pine ecosystem: interpretation of PTR-MS mass spectra, Atmos. Chem. Phys., 10, 1759–1771, http://dx.doi.org/10.5194/acp-10-1759-2010doi:10.5194/acp-10-1759-2010, 2010.

Krinke, S. and Wahner, A.: Formaldehyde and ozone deposition velocities determined above a deciduous forest during summer, Eos Trans AGU, 80(46), Fall Meeting Supplement, 1999.

Kurpius, M R. and Goldstein, A H.: Gas-phase chemistry dominates \chemO_3 loss to a forest, implying a source of aerosols and hydroxyl radicals to the atmosphere, Geophysical Research Letters, 30, 1371, http://dx.doi.org/10.1029/2002gl016785doi:10.1029/2002gl016785, 2003.

LaFranchi, B. W., Wolfe, G. M., Thornton, J. A., Harrold, S. A., Browne, E. C., Min, K. E., Wooldridge, P. J., Gilman, J. B., Kuster, W. C., Goldan, P. D., de Gouw, J. A., McKay, M., Goldstein, A. H., Ren, X., Mao, J., and Cohen, R. C.: Closing the peroxy acetyl nitrate budget: observations of acyl peroxy nitrates (PAN, PPN, and MPAN) during BEARPEX 2007, Atmos. Chem. Phys., 9, 7623–7641, http://dx.doi.org/10.5194/acp-9-7623-2009doi:10.5194/acp-9-7623-2009, 2009.

Lee, A., Goldstein, A H., Kroll, J H., Ng, N L., Varutbangkul, V., Flagan, R C., and Seinfeld, J H.: Gas-phase products and secondary aerosol yields from the photooxidation of 16 different terpenes, J. Geophys. Res.-Atmos., 111, D17305, http://dx.doi.org/10.1029/2006jd007050doi:10.1029/2006jd007050, 2006.

Lee, X., Massman, W., and Law., B.: Handbook of Micrometeorology – A Guide for Surface Flux Measurement and Analysis, Kluwer Academic Publishers, Dordrecht, The Netherlands, 2004.

Lee, Y N., Zhou, X., Kleinman, L I., Nunnermacker, L J., Springston, S R., Daum, P H., Newman, L., Keigley, W G., Holdren, M W., Spicer, C W., Young, V., Fu, B., Parrish, D D., Holloway, J., Williams, J., Roberts, J M., Ryerson, T B., and Fehsenfeld, F C.: Atmospheric chemistry and distribution of formaldehyde and several multioxygenated carbonyl compounds during the 1995 Nashville Middle Tennessee Ozone Study, J. Geophys. Res.-Atmos., 103, 22 449–22 462, 1998.

Lelieveld, J., Butler, T M., Crowley, J N., Dillon, T J., 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.

Lindinger, W., Hansel, A., and Jordan, A.: Proton-transfer-reaction mass spectrometry (PTR-MS): on-line monitoring of volatile organic compounds at pptv levels, Chem. Soc. Rev., 27, 347–375, 1998.

Massman, W J.: A review of the molecular diffusivities of \chemH_2O, \chemCO_2, \chemCH_4, \chemCO, \chemO_3, \chemSO_2, \chemNH_3, \chemN_2O, \chemNO_3 and \chemNO_2 in air, \chemO_2 and \chemN_2 near STP, Atmos. Environ. , 32, 1111–1127, 1998.

McManus, J B., Zahniser, M S., Nelson, D D., Shorter, J H., Herndon, S., Wood, E., and Wehr, R.: Application of quantum cascade lasers to high-precision atmospheric trace gas measurements, Opt. Eng., 49, 111 124, http://dx.doi.org/10.1117/1.3498782doi:10.1117/1.3498782, 2010.

Monteith, J.: Evaporation and Environment, Sym. Soc. Exp. Biol., 19, 205–234, 1965.

Monteith, J. and Unsworth, M.: Principles of Environmental Physics, Edward Arnold, London, 2nd edn., 1990.

Munger, J W., Jacob, D J., Daube, B C., Horowitz, L W., Keene, W C., and Heikes, B G.: Formaldehyde, Glyoxal, and Methylglyoxal in Air and Cloudwater at a Rural Mountain Site in Central Virginia, J. Geophys. Res.-Atmos., 100, 9325–9333, 1995.

Rayment, M B. and Jarvis, P G.: An improved open chamber system for measuring soil \chemCO_2 effluxes in the field, J. Geophys. Res.-Atmos., 102, 28 779–28 784, 1997.

Sadanaga, Y., Yoshino, A., Watanabe, K., Yoshioka, A., Wakazono, Y., Kanaya, Y., and Kajii, Y.: Development of a measurement system of OH reactivity in the atmosphere by using a laser-induced pump and probe technique, Rev. Sci. Instrum., 75, 2648–2655, http://dx.doi.org/10.1063/1.1775311doi:10.1063/1.1775311, 2004.

Schade, G W., Goldstein, A H., Gray, D W., and Lerdau, M T.: Canopy and leaf level 2-methyl-3-buten-2-ol fluxes from a ponderosa pine plantation, Atmos. Environ. , 34, 3535–3544, 2000.

Seco, R., Penuelas, J., and Filella, I.: Short-chain oxygenated VOCs: Emission and uptake by plants and atmospheric sources, sinks, and concentrations, Atmos. Environ. , 41, 2477–2499, http://dx.doi.org/10.1016/j.atmosenv.2006.11.029doi:10.1016/j.atmosenv.2006.11.029, 2007.

Seco, R., Penuelas, J., and Filella, I.: Formaldehyde emission and uptake by Mediterranean trees \textitQuercus ilex and \textitPinus halepensis, Atmos. Environ., 42, 7907–7914, http://dx.doi.org/10.1016/j.atmosenv.2008.07.006doi:10.1016/j.atmosenv.2008.07.006, 2008.

Sinha, V., Williams, J., Lelieveld, J., Ruuskanen, T M., Kajos, M K., Patokoski, J., Hellen, H., Hakola, H., Mogensen, D., Boy, M., Rinne, J., and Kulmala, M.: OH Reactivity Measurements within a Boreal Forest: Evidence for Unknown Reactive Emissions, Envir. Sci. Tech., 44, 6614–6620, http://dx.doi.org/10.1021/es101780bdoi:10.1021/es101780b, 2010.

Slemr, J., Junkermann, W., and VolzThomas, A.: Temporal variations in formaldehyde, acetaldehyde and acetone and budget of formaldehyde at a rural site in southern Germany, Atmos. Environ. , 30, 3667–3676, 1996.

Sumner, A L., Shepson, P B., Couch, T L., Thornberry, T., Carroll, M A., Sillman, S., Pippin, M., Bertman, S., Tan, D., Faloona, I., Brune, W., Young, V., Cooper, O., Moody, J., and Stockwell, W.: A study of formaldehyde chemistry above a forest canopy, J. Geophys. Res.-Atmos., 106, 24 387–24 405, 2001.

Tan, D., Faloona, I., Simpas, J B., Brune, W., Shepson, P B., Couch, T L., Sumner, A L., Carroll, M A., Thornberry, T., Apel, E., Riemer, D., and Stockwell, W.: \chemHO_x budgets in a deciduous forest: Results from the PROPHET summer 1998 campaign, J. Geophys. Res.-Atmos., 106, 24 407–24 427, 2001.

Tanner, D J., Jefferson, A., and Eisele, F L.: Selected ion chemical ionization mass spectrometric measurement of OH, J. Geophys. Res.-Atmos., 102, 6415–6425, 1997.

Teske, M E. and Thistle, H W.: A library of forest canopy structure for use in interception modeling, Forest Ecol. Manag., 198, 341–350, http://dx.doi.org/10.1016/j.foreco.2004.05.031doi:10.1016/j.foreco.2004.05.031, 2004.

Turnipseed, A A., Huey, L G., Nemitz, E., Stickel, R., Higgs, J., Tanner, D J., Slusher, D L., Sparks, J P., Flocke, F., and Guenther, A.: Eddy covariance fluxes of peroxyacetyl nitrates (\chemPANs) and \chemNO_y to a coniferous forest, J. Geophys. Res.-Atmos., 111, http://dx.doi.org/10.1029/2005jd006631doi:10.1029/2005jd006631, 2006.

Villanueva-Fierro, I., Popp, C J., and Martin, R S.: Biogenic emissions and ambient concentrations of hydrocarbons, carbonyl compounds and organic acids from ponderosa pine and cottonwood trees at rural and forested sites in Central New Mexico, Atmos. Environ., 38, 249–260, http://dx.doi.org/10.1016/j.atmosenv.2003.09.051doi:10.1016/j.atmosenv.2003.09.051, 2004.

Volz-Thomas, A., Lerner, A., Patz, H W., Schultz, M., McKenna, D S., Schmitt, R., Madronich, S., and Roth, E P.: Airborne measurements of the photolysis frequency of \chemNO_2, J. Geophys. Res.-Atmos., 101, 18 613–18 627, 1996.

Weibring, P., Richter, D., Walega, J G., and Fried, A.: First demonstration of a high performance difference frequency spectrometer on airborne, Opt. Express, 15, 13 476–13 495, 2007.

Wert, B P., Fried, A., Henry, B., and Cartier, S.: Evaluation of inlets used for the airborne measurement of formaldehyde, J. Geophys. Res.-Atmos., 107, http://dx.doi.org/10.1029/2001jd001072doi:10.1029/2001jd001072, 2002.

Wesely, M L.: Parameterization of Surface Resistances to Gaseous Dry Deposition in Regional-Scale Numerical-Models, Atmos. Environ. , 23, 1293–1304, 1989.

Wesely, M L. and Hicks, B B.: A review of the current status of knowledge on dry deposition, Atmos. Environ. , 34, 2261–2282, 2000.

Whalley, L. K., Edwards, P. M., Furneaux, K. L., Goddard, A., Ingham, T., Evans, M. J., Stone, D., Hopkins, J. R., Jones, C. E., Karunaharan, A., Lee, J. D., Lewis, A. C., Monks, P. S., Moller, S. J., and Heard, D. E.: Quantifying the magnitude of a missing hydroxyl radical source in a tropical rainforest, Atmos. Chem. Phys., 11, 7223–7233, http://dx.doi.org/10.5194/acp-11-7223-2011doi:10.5194/acp-11-7223-2011, 2011.

Wisthaler, A., Apel, E. C., Bossmeyer, J., Hansel, A., Junkermann, W., Koppmann, R., Meier, R., M�ller, K., Solomon, S. J., Steinbrecher, R., Tillmann, R., and Brauers, T.: Technical Note: Intercomparison of formaldehyde measurements at the atmosphere simulation chamber SAPHIR, Atmos. Chem. Phys., 8, 2189–2200, http://dx.doi.org/10.5194/acp-8-2189-2008doi:10.5194/acp-8-2189-2008, 2008.

Wolfe, G. M. and Thornton, J. A.: The Chemistry of Atmosphere-Forest Exchange (CAFE) Model - Part 1: Model description and characterization, Atmos. Chem. Phys., 11, 77–101, http://dx.doi.org/10.5194/acp-11-77-2011doi:10.5194/acp-11-77-2011, 2011.

Wolfe, G. M., Thornton, J. A., Yatavelli, R. L. N., McKay, M., Goldstein, A. H., LaFranchi, B., Min, K.-E., and Cohen, R. C.: Eddy covariance fluxes of acyl peroxy nitrates (PAN, PPN and MPAN) above a Ponderosa pine forest, Atmos. Chem. Phys., 9, 615–634, http://dx.doi.org/10.5194/acp-9-615-2009doi:10.5194/acp-9-615-2009, 2009.

Xu, L K., Furtaw, M D., Madsen, R A., Garcia, R L., Anderson, D J., and McDermitt, D K.: On maintaining pressure equilibrium between a soil \chemCO_2 flux chamber and the ambient air, J. Geophys. Res.-Atmos., 111, D08S10, http://dx.doi.org/10.1029/2005jd006435doi:10.1029/2005jd006435, 2006.

Zhang, L M., Moran, M D., Makar, P A., Brook, J R., and Gong, S L.: Modelling gaseous dry deposition in AURAMS: a unified regional air-quality modelling system, Atmos. Environ., 36, 537–560, 2002.

Zhang, Q., Jimenez, J L., Canagaratna, M R., Allan, J D., Coe, H., Ulbrich, I., Alfarra, M R., Takami, A., Middlebrook, A M., Sun, Y L., Dzepina, K., Dunlea, E., Docherty, K., DeCarlo, P F., Salcedo, D., Onasch, T., Jayne, J T., Miyoshi, T., Shimono, A., Hatakeyama, S., Takegawa, N., Kondo, Y., Schneider, J., Drewnick, F., Borrmann, S., Weimer, S., Demerjian, K., Williams, P., Bower, K., Bahreini, R., Cottrell, L., Griffin, R J., Rautiainen, J., Sun, J Y., Zhang, Y M., and Worsnop, D R.: Ubiquity and dominance of oxygenated species in organic aerosols in anthropogenically-influenced Northern Hemisphere midlatitudes, Geophys. Res. Lett., 34, L13 801, http://dx.doi.org/10.1029/2007gl029979doi:10.1029/2007gl029979, 2007.

Zheng, W., Flocke, F. M., Tyndall, G. S., Swanson, A., Orlando, J. J., Roberts, J. M., Huey, L. G., and Tanner, D. J.: Characterization of a thermal decomposition chemical ionization mass spectrometer for the measurement of peroxy acyl nitrates (PANs) in the atmosphere, Atmos. Chem. Phys., 11, 6529–6547, http://dx.doi.org/10.5194/acp-11-6529-2011doi:10.5194/acp-11-6529-2011, 2011.