References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-8-3899-2008

Observations of HNO3, ΣAN, ΣPN and NO2 fluxes: evidence for rapid HOx chemistry within a pine forest canopy

Farmer

D. K.

¹ Cohen

R. C.

¹ ² ³

Department of Chemistry, University of California Berkeley, Berkeley, CA, USA

Department of Earth and Planetary Science, University of California Berkeley, Berkeley, CA 94720, USA

Energy and Environment Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA

22 07 2008

8 14 3899 3917

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Measurements of exchange of reactive nitrogen oxides between the atmosphere and a ponderosa pine forest in the Sierra Nevada Mountains are reported. During winter, we observe upward fluxes of NO2, and downward fluxes of total peroxy and peroxy acyl nitrates (ΣPNs), total gas and particle phase alkyl and multifunctional alkyl nitrates (ΣANs(g+p)), and the sum of gaseous HNO3 and semi-volatile NO3− particles (HNO3(g+p)). We use calculations of the vertical profile and flux of NO, partially constrained by observations, to show that net midday ΣNOyi fluxes in winter are –4.9 ppt m s−1. The signs and magnitudes of these wintertime individual and ΣNOyi fluxes are in the range of prior measurements. In contrast, during summer, we observe downward fluxes only of ΣANs(g+p), and upward fluxes of HNO3(g+p), ΣPNs and NO2 with signs and magnitudes that are unlike most, if not all, previous observations and analyses of fluxes of individual nitrogen oxides. The results imply that the mechanisms contributing to NOy fluxes, at least at this site, are much more complex than previously recognized. We show that the observations of upward fluxes of HNO3(g+p) and σPNs during summer are consistent with oxidation of NO2 and acetaldehyde by an OH x residence time of 1.1×1010 molec OH cm−3 s, corresponding to 3 to 16×107 molecules cm−3 OH within the forest canopy for a 420 to 70 s canopy residence time. We show that ΣAN(g+p) fluxes are consistent with this range in OH if the reaction of OH with ΣANs produces either HNO3 or NO2 with a 6–30% yield. Calculations of NO fluxes constrained by the NO2 observations and the inferred OH indicate that NOx fluxes are downward into the canopy because of the substantial conversion of NOx to HNO3 and σPNs in the canopy. Even so, we derive that NOx emission fluxes of ~15 ng(N) m−2 s−1 at midday during summer are required to balance the NOx and NOy flux budgets. These fluxes are partly explained by estimates of soil emissions (estimated to be between 3 and 6 ng(N) m−2 s-1). One possibility for the remainder of the NOx source is large HONO emissions. Alternatively, the 15 ng(N) m−2 s−1 emission estimate may be too large, and the budget balanced if the deposition of HNO3 and σPNs is slower than we estimate, if there are large errors in either our understanding of peroxy radical chemistry, or our assumptions that the budget is required to balance because the fluxes do not obey similarity theory.

References 1

Atkinson, R., Aschmann, S. M., Carter, W. P. L., Winer, A. M., and Pitts, J. N.: Alkyl nitrate formation from the NOx-air photooxidations of C2-C$_8$ n-alkanes, J. Phys. Chem., 86, 4563–4569, 1982.

Atkinson, R., Aschmann, S. M., Arey, J., and Shorees, B.: Formation of OH radicals in the gas-phase reactions of O3 with a series of terpenes, J. Geophys. Res., 97, 6065–6073, 1992.

Bauer, M. R., Hultman, N. E., Panek, J. A., and Goldstein, A. H.: Ozone deposition to a ponderosa pine plantation in the Sierra Nevada Mountains (CA): A comparison of two different climatic years, J. Geophys. Res., 105, 22 123–22 136, 2000.

Bertram, T. H. and Cohen, R. C.: A prototype instrument for the detection of semi-volatile organic and inorganic nitrate aerosol, Eos Trans. AGU, 84, 2003.

Bertram, T. H.: Observational constraints for the source strengths, transport and partitioning of reactive nitrogen on regional and global scales, PhD thesis, University of California, Berkeley, Berkeley, 2006.

Brost, R., Delany, A., and Huebert, B.: Numerical modeling of concentrations and fluxes of HNO3, NH3 and NH4NO3 near the surface, J. Geophys. Res., 93, 7137–7152, 1988.

Brown, S. S., Dibb, J. E., Stark, H., Aldener, M., Vozella, M., Whitlow, S., Williams, E. J., Lerner, B. M., Jakoubek, R., Middlebrook, A. M., DeGouw, J. A., Warneke, C., Goldan, P. D., Kuster, W. C., Angevine, W. M., Sueper, D. T., Quinn, P. K., Bates, T. S., Meagher, J. F., Fehsenfeld, F. C., and Ravishankara, A. R.: Nighttime removal of NOx in the summer marine boundary layer, Geophys. Res. Lett., 31, L07108, doi:10.1029/2004GL019412, 2004.

Carroll, J. J. and Dixon, A. J.: Regional scale transport over complex terrain, a case study: tracing the Sacramento plume in the Sierra Nevada of California, Atmos. Eniviron., 36, 3745–3758, 2002.

Carslaw, N., Creasey, D. J., Harrison, D., Heard, D. E., Hunter, M. C., Jacobs, P. J., Jenkin, M. E., Lee, J. D., Lewis, A. C., Pilling, M. J., Saunders, S. M., and Seakins, P. W.: OH and HO2 radical chemistry in a forested region of north-western Greece, Atmos. Eniviron., 35, 4725–4737, 2001.

Ciccioli, P., Brancaleoni, E., Frattoni, M., Di Palo, V., Valentini, R., Tirone, G., Seufert, G., Bertin, N., Hansen, U., Csiky, O., Lenz, R., and Sharma, M.: Emission of reactive terpene compounds from orange orchards and their removal by within-canopy processes, J. Geophys. Res., 104, 8077–8094, 1999.

Cleary, P. A., Murphy, J. G., Wooldridge, P. J., Day, D. A., Millet, D. B., McKay, M., Goldstein, A. H., and Cohen, R. C.: Observations of total alkyl nitrates within the Sacramento Urban Plume, Atmos. Chem. Phys. Discuss., 5, 4801–4843, 2005.

Collins, W. J., Derwent, R. G., Johnson, C. E., and Stevenson, D. S.: The oxidation of organic compounds in the troposphere and their global warming potentials, Clim. Change, 52, 453–479, 2002.

Day, D. A., Wooldridge, P. J., Dillon, M. B., Thornton, J. A., and Cohen, R. C.: A thermal dissociation laser-induced fluorescence instrument for in situ detection of NO2, peroxy nitrates, alkyl nitrates, and HNO3, J. Geophys. Res., 107, 4046, doi:10.1029/2001JD000779, 2002.

Day, D. A.: Observations of NO2, total peroxy nitrates, total alkyl nitrates, and HNO3 in the Mid-Sierras and Sacramento plume using Thermal Dissociation-Laser Induced Fluorescence, PhD thesis, University of California, Berkeley, Berkeley, 2003.

Day, D. A., Dillon, M. B., Wooldridge, P. J., Thornton, J. A., Rosen, R. S., Wood, E. C., and Cohen, R. C.: On alkyl nitrates, O3, and the "missing NOy", J. Geophys. Res., 108(D16), 4501, doi:10.1029/2003JD003685 , 2003.

Day, D. A., Wooldridge, P. J., and Cohen, R. C.: Observations of the temperature dependence of HNO3, $§igma $ANs, $§igma $PNs, and NO2, Atmos. Chem. Phys., 8, 1867–1879, 2008.

Di Carlo, P., Brune, W. H., Martinez, M., Harder, H., Lesher, R., Ren, X. R., 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.

Dillon, M. B., Lamanna, M. S., Schade, G. W., Goldstein, A. H., and Cohen, R. C.: Chemical evolution of the Sacramento urban plume: Transport and oxidation, J. Geophys. Res., 107, 4045, doi:10.1029/2001JD000969, 2002.

Donahue, N. M., Kroll, J. H., Anderson, J. G., and Demerjian, K. L.: Direct observation of OH production from the ozonolysis of olefins, Geophys. Res. Lett., 25, 59–62, 1998.

Doskey, P. V., Kotamarthi, V. R., Fukui, Y., Cook, D. R., Breitbeil, F. W., and Wesely, M. L.: Air-surface exchange of peroxyacetyl nitrate at a grassland site, J. Geophys. Res., 109, 13 153–13 168, 2004.

Faloona, I., Tan, D., Brune, W., Hurst, J., Barket, D., Couch, T. L., Shepson, P., Apel, E., Riemer, D., Thornberry, T., Carroll, M. A., Sillman, S., Keeler, G. J., Sagady, J., Hooper, D., and Paterson, K.: Nighttime observations of anomalously high levels of hydroxyl radicals above a deciduous forest canopy, J. Geophys. Res., 106, 24 315–24 333, 2001.

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 NO2 fluxes using eddy covariance, Atmos. Chem. Phys., 6, 3471–3486, 2006.

Ferronato, C., Orlando, J. J., and Tyndall, G. S.: Rate and mechanism of the reactions of OH and Cl with 2-methyl-3-buten-2-ol, J. Geophys. Res., 103, 25 579–25 586, 1998.

Fiore, A. M., Horowitz, L. W., Purves, D. W., Levy, H., Evans, M. J., Wang, Y. X., Li, Q. B., and Yantosca, R. M.: Evaluating the contribution of changes in isoprene emissions to surface ozone trends over the eastern United States, J. Geophys. Res., 110, 12303, doi:10.1029/2004JD005485, 2005.

Fischer, M. and Littlejohn, D.: M. L. Fischer and D. Littlejohn, : Ammonia at Blodgett Forest, Sierra Nevada, USA, Atmos. Chem. Phys. Discuss., 7, 14139–14169, 2007.

Fitzjarrald, D. R. and Lenschow, D. H.: Mean Concentration and Flux Profiles for Chemically Reactive Species in the Atmospheric Surface-Layer, Atmos. Eniviron., 17, 2505–2512, 1983.

Forkel, R., Klemm, O., Graus, M., Rappengluck, B., Stockwell, W. R., Grabmer, W., Held, A., Hansel, A., and Steinbrecher, R.: Trace gas exchange and gas phase chemistry in a Norway spruce forest: A study with a coupled 1-dimensional canopy atmospheric chemistry emission model, Atmos. Eniviron., 40, 28–42, 2006.

Fuentes, J. D., Wang, D., Neumann, H. H., Gillespie, T. J., DenHartog, G., and Dann, T. F.: Ambient biogenic hydrocarbons and isoprene emissions from a mixed deciduous forest, J. Atmos. Chem., 25, 67–95, 1996.

Gao, W., Wesely, M. L., and Doskey, P. V.: Numerical Modeling of the Turbulent-Diffusion and Chemistry of NOx, O3, Isoprene, and Other Reactive Trace Gases in and above a Forest Canopy, J. Geophys. Res., 98, 18 339–18 353, 1993.

Giacopelli, P., Ford, K., Espada, C., and Shepson, P. B.: Comparison of the measured and simulated isoprene nitrate distributions above a forest canopy, J. Geophys. Res., 110, D01304, doi:10.1029/2004JD005123, 2005.

Goldstein, A. H., Hultman, N. E., Fracheboud, J. M., Bauer, M. R., Panek, J. A., Xu, M., Wi, Y., Guenther, A. B., and Baugh, W.: Effects of climate variability on the carbon dioxide, water and sensible heat fluxes above a ponderosa pine plantation in the Sierra Nevada (CA), Agric. Forest Met., 101, 113–129, 2000.

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.

Guenther, A., Hewitt, C. N., Erickson, D., Fall, R., Geron, C., Graedel, T., Harley, P., Klinger, L., Lerdau, M., Mckay, W. A., Pierce, T., Scholes, B., Steinbrecher, R., Tallamraju, R., Taylor, J., and Zimmerman, P.: A Global-Model of Natural Volatile Organic-Compound Emissions, J. Geophys. Res., 100, 8873–8892, 1995.

Hasson, A. S., Tyndall, G. S., and Orlando, J. J.: A product yield study of the reaction of HO2 radicals with ethyl peroxy (C2H$_5$O$_2)$, acetyl peroxy (CH3C(O)O$_2)$, and acetonyl peroxy (CH3C(O)CH2O$_2)$ radicals, J. Phys. Chem. A, 108, 5979–5989, 2004.

Helmig, D., Ortega, J., Guenther, A., Herrick, J. D., and Geron, C.: Sesquiterpene emissions from loblolly pine and their potential contribution to biogenic aerosol formation in the Southeastern US, Atmos. Eniviron., 40, 4150–4157, 2006.

Helmig, D., Ortega, J., Duhl, T., Tanner, D., Guenther, A., Harley, P., Wiedinmyer, C., Milford, J., and Sakulyanontvittaya, T.: Sesquiterpene emissions from pine trees – Identifications, emission rates and flux estimates for the contiguous United States, Environ. Sci. Technol., 41, 1545–1553, 2007.

Herman, D. J., Halverson, L. J., and Firestone, M. K.: Nitrogen dynamics in an annual grassland: oak canopy, climate, and microbial population effects, Ecological Applications, 13, 593–604, 2003.

Holzinger, R., Lee, A., McKay, M., and Goldstein, A. H.: Seasonal variability of monoterpene emission factors for a ponderosa pine plantation in California, Atmos. Chem. Phys. Discuss., 5, 8791–8810, 2005a.

Holzinger, R., Lee, A., Paw U, K. T., and Goldstein, A. H.: Observations of oxidation products above a forest imply biogenic emissions of very reactive compounds, Atmos. Chem. Phys., 5, 67–75, 2005b.

Holzke, C., Hoffmann, T., Jaeger, L., Koppmann, R. and Zimmer, W.: Diurnal and seasonal variation of monoterpene and sesquiterpene emissions from Scots pine (\textitPinus sylvestris L.), Atmos. Eniviron., 40, 3174-3185, 2006.

Horii, C. V., Munger, J. W., Wofsy, S. C., Zahniser, M., Nelson, D., and McManus, J. B.: Fluxes of nitrogen oxides over a temperate deciduous forest, J. Geophys. Res., 109, D08305, doi:10.1029/2003JD004326, 2004.

Horii, C. V., Munger, J. W., Wofsy, S. C., Zahniser, M., Nelson, D., and McManus, J. B.: Atmospheric reactive nitrogen concentration and flux budgets at a Northeastern US forest site, Agric. Forest Met., 133, 210–225, 2005.

Horowitz, L. W., Liang, J. Y., Gardner, G. M., and Jacob, D. J.: Export of reactive nitrogen from North America during summertime: Sensitivity to hydrocarbon chemistry, J. Geophys. Res., 103, 13 451–13 476, 1998.

Horowitz, L. W., Fiore, A. M., Milly, G. P., Cohen, R. C., Perring, A., Wooldridge, P. J., Hess, P. G., Emmons, L. K., and Lamarque, J.-F.: Observational constraints on the chemistry of isoprene nitrates over the eastern United States, J. Geophys. Res., 112, D12S08, doi:10.1029/2006JD007747, 2007.

Huebert, B. J., Luke, W. T., Delany, A. C., and Brost, R. A.: Measurements of concentrations and dry surface fluxes of atmospheric nitrates in the presence of ammonia, J. Geophys. Res., 93, 7127–7136, 1988.

Kanakidou, M., Seinfeld, J. H., Pandis, S. N., Barnes, I., Dentener, F. J., Facchini, M. C., Van Dingenen, R., Ervens, B., Nenes, A., Nielsen, C. J., Swietlicki, E., Putaud, J. P., Balkanski, Y., Fuzzi, S., Horth, J., Moortgat, G. K., Winterhalter, R., Myhre, C. E. L., Tsigaridis, K., Vignati, E., Stephanou, E. G., and Wilson, J.: Organic aerosol and global climate modelling: a review, Atmos. Chem. Phys., 5, 1053–1123, 2005.

Kastler, J., Jarman, W., and Ballschmiter, K.: Multifunctional organic nitrates as constituents in European and US urban photo-smog, Fresen J Anal Chem, 368, 244–249, 2000.

Kleffmann, J., Gavriloaiei, T., Hofzumahaus, A., Holland, F., Koppmann, R., Rupp, L., Schlosser, E., Siese, M., and Wahner, A.: Daytime formation of nitrous acid: A major source of OH radicals in a forest, Geophys. Res. Lett., 32, L05818, doi:10.1029/2005GL022524, 2005.

Kossmann, M., Vogtlin, R., Corsmeier, U., Vogel, B., Fiedler, F., Binder, H. J., Kalthoff, N., and Beyrich, F.: Aspects of the convective boundary layer structure over complex terrain, Atmos. Eniviron., 32, 1323–1348, 1998.

Kramm, G., Muller, H., Fowler, D., Hofken, K. D., Meixner, F. X., and Schaller, E.: A Modified Profile Method for Determining the Vertical Fluxes of NO, NO2, Ozone, and HNO3 in the Atmospheric Surface-Layer, J. Atmos. Chem., 13, 265–288, 1991.

Kramm, G., Dlugi, R., Dollard, G. J., Foken, T., Molders, N., Muller, H., Seiler, W., and Sievering, H.: On the Dry Deposition of Ozone and Reactive Nitrogen Species, Atmos. Eniviron., 29, 3209–3231, 1995.

Kroll, J. H., Hanisco, T. F., Donahue, N. M., Demerjian, K. L., and Anderson, J. G.: Accurate, direct measurements of OH yields from gas-phase ozone-alkene reactions using an in situ LIF instrument, Geophys. Res. Lett., 28, 3863–3866, 2001.

Kroll, J. H., Ng, N. L., Murphy, S. M., Flagan, R. C., and Seinfeld, J. H.: Secondary organic aerosol formation from isoprene photooxidation under high-NOx conditions, Geophys. Res. Lett., 32, L18808, doi:10.1029/2005GL023637, 2005.

Kurpius, M. R. and Goldstein, A. H.: Gas-phase chemistry dominates O3 loss to a forest, implying a source of aerosols and hydroxyl radicals to the atmosphere, Geophys. Res. Lett., 30, 1371–1375, doi:10.1029/2002GL016785, 2003.

Lamanna, M. S. and Goldstein, A. H.: In situ measurements of C2-C$_10$ volatile organic compounds above a Sierra Nevada ponderosa pine plantation, J. Geophys. Res., 104, 21 247–21 262, 1999.

Larsen, B. R., Di Bella, D., Glasius, M., Winterhalter, R., Jensen, N. R., and Hjorth, J.: Gas-phase OH oxidation of monoterpenes: Gaseous and particulate products, J. Atmos. Chem., 38, 231–276, 2001.

Lee, A., Goldstein, A. H., Keywood, M. D., Gao, S., Varutbangkul, V., Bahreini, R., Ng, N. L., Flagan, R. C., and Seinfeld, J. H.: Gas-phase products and secondary aerosol yields from the ozonolysis of ten different terpenes, J. Geophys. Res., 111, D07302, doi:10.10.1029/2005JD006437, 2006.

Lefer, B. L., Talbot, R. W., and Munger, J. W.: Nitric acid and ammonia at a rural northeastern U.S. site, J. Geophys. Res., 104, 1645–1662, 1999.

Lelieveld, J., van Aardenne, J., Fischer, H., de Reus, M., Williams, J., and Winkler, P.: Increasing ozone over the Atlantic Ocean, Science, 304, 1483–1487, 2004.

Madronich, S. and Flocke, S.: The role of solar radiation in atmospheric chemistry, in \textitHandbook of Environmental Chemistry, edited by Boule, P., Springer-Verlag, Heidelberg, 1998.

Martens, C. S., Shay, T. J., Mendlovitz, H. P., Matross, D. M., Saleska, S. R., Wofsy, S. C., Woodward, W. S., Menton, M. C., De Moura, J. M. S., Crill, P. M., De Moraes, O. L. L., and Lima, R. L.: Radon fluxes in tropical forest ecosystems of Brazilian Amazonia: night-time CO2 net ecosystem exchange derived from radon and eddy covariance methods, Global Change Biology, 10, 618–629, 2004.

Meyers, T. P., Huebert, B. J., and Hicks, B. B.: HNO3 Deposition to a Deciduous Forest, Bound.-Lay. Meteorol., 49, 395–410, 1989.

Munger, J. W., Wofsy, S. C., Bakwin, P. S., Fan, S.-M., Goulden, M. L., Daube, B. C., Goldstein, A. H., Moore, K. E., and Fitzjarrald, D. R.: Atmospheric deposition of reactive nitrogen oxides and ozone in a temperate deciduous forest and a subarctic woodland. 1. Measurements and mechanisms, J. Geophys. Res., 101, 12 639–12 657, 1996.

Murphy, J. G., Day, D. A., Cleary, P. A., Wooldridge, P. J., and Cohen, R. C.: Observations of the diurnal and seasonal trends in nitrogen oxides in the western Sierra Nevada, Atmos. Chem. Phys., 6, 5321–5338, 2006a.

Murphy, J. G., Day, D. A., Cleary, P. A., Wooldridge, P. J., Millet, D. B., Goldstein, A., and Cohen, R. C.: The weekend effect within and downwind of Sacramento: Part 1. Observations of ozone, nitrogen oxides, and VOC reactivity, Atmos. Chem. Phys. Discussions, 6, 11 427–11 464, 2006b.

Murphy, J. G., Day, D. A., Cleary, P. A., Wooldridge, P. J., Millet, D. B., Goldstein, A. H., and Cohen, R. C.: The weekend effect within and downwind of Sacramento: Part 2. Observational evidence for chemical and dynamical contributions, Atmos. Chem. Phys. Discuss., 6, 11 971–12 019, 2006c.

Neftel, A., Blatter, A., Hesterberg, R., and Staffelbach, T.: Measurements of concentration gradients of HNO2 and HNO3 over a semi-natural ecosystem, Atmos. Eniviron., 30, 3017–3025, 1996.

Nemitz, E., Sutton, M. A., Wyers, G. P., and Jongejan, P. A. C.: Gas-particle interactions above a Dutch heathland: 1. Surface exchange fluxes of NH3, SO2, HNO3 and HCl, Atmos. Chem. Phys., 4, 989–1005, 2004.

Neuman, J. A., Huey, L. G., Ryerson, T. B., and Fahey, D. W.: Study of inlet materials for sampling atmospheric nitric acid, Environ. Sci. Technol., 33, 1133–1136, 1999.

Nielsen, O. J., Sidebottom, H. W., Donlon, M., and Treacy, J.: Rate constants for the gas-phase reactions of OH radicals and Cl atoms with normal-alkyl nitrites at atmospheric-pressure and 298-K, Int. J. Chem. Kinet., 23, 1095–1109, 1991.

O'Brien, J. M., Shepson, P. B., Muthuramu, K., Hao, C., Niki, H., Hastie, D. R., Taylor, R., and Roussel, P. B.: Measurements of Alkyl and Multifunctional Organic Nitrates at a Rural Site in Ontario, J. Geophys. Res., 100, 22 795–22 804, 1995.

O'Brien, J. M., Czuba, E., Hastie, D. R., Francisco, J. S., and Shepson, P. B.: Determination of the hydroxy nitrate yields from the reaction of C2-C$_6$ alkenes with OH in the presence of NO, J. Phys. Chem. A, 102, 8903–8908, 1998.

Paulson, S. E. and Orlando, J. J.: The reactions of ozone with alkenes: An important source of HOx in the boundary layer, Geophys. Res. Lett., 23, 3727–3730, 1996.

Perez, I., Wooldridge, P., and Cohen, R. C.: Laboratory evaluation of a novel thermal dissociation chemiluminescence method for in situ detection of nitrous acid, Atmos. Eniviron., 41, 3993–4001, 2007.

Poschl, 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.

Pryor, S. and Klemm, O.: Experimentally derived estimates of nitric acid dry deposition velocity and viscous sub-layer resistance at a conifer forest, Atmos. Eniviron., 38, 2769–2777, 2004.

Pryor, S. C., Barthelmie, R. J., Jensen, B., Jensen, N. O., and Sorensen, L. L.: HNO3 fluxes to a deciduous forest derived using gradient and REA methods, Atmos. Eniviron., 36, 5993–5999, 2002.

Raivonen, M., Bonn, B., Sanz, M., Vesala, T., Kulmala, M. and Hari, P.: UV-induced NO$_y$ emissions from Scots pine: Could they originate from photolysis of deposited HNO3?, Atmos. Eniviron., 40, 6201–6213, 2006.

Ren, X., Olson, J. R., Crawford, J. H., Brune, W. H., Mao, J., Long, R. B., 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.: HOx Observation and Model Comparison during INTEX-A 2004, J. Geophys. Res., 113, D05310, doi:10.1029/2007JD009166, 2008.

Rinne, J., Taipale, R., Markkanen, T., Ruuskanen, T. M., Hellén, H., Kajos, M. K., Vesala, T., and Kulmala, M.: Hydrocarbon fluxes above a Scots pine forest canopy: measurements and modeling, Atmos. Chem. Phys., 7, 3361–3372, 2007.

Rondon, A., Johansson, C., and Granat, L.: Dry Deposition of Nitrogen-Dioxide and Ozone to Coniferous Forests, J. Geophys. Res., 98, 5159–5172, 1993.

Rondon, A. and Granat, L.: Studies on the Dry Deposition of NO2 to Coniferous Species at Low NO2 Concentrations, Tellus B, 46, 339–352, 1994.

Rosen, R. S., Wood, E. C., Wooldridge, P. J., Thornton, J. A., Day, D. A., Kuster, W., Williams, E. J., Jobson, B. T., and Cohen, R. C.: Observations of total alkyl nitrates during Texas Air Quality Study 2000: Implications for O3 and alkyl nitrate photochemistry, J. Geophys. Res., 109, D07303, doi:10.1029/2003JD004227, 2004.

Rummel, U., Ammann, C., Gut, A., Meixner, G. X., and Andreae, M. O.: Eddy covariance measurements of nitric oxide flux within an Amazonian rain forest, J. Geophys. Res., 107, 8050, doi:10.1029/2001JD000520, 2002.

Sander, S. P., Finlayson-Pitts, B. J., Friedl, R. R., Golden, D. M., Huie, R. E., Keller-Rudek, H., Kolb, C. E., Kurylo, M. J., Molina, M. J., Moortgat, G. K., Orkin, V. L., Ravishankara, A. R., and Wine, P. H.: Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies, Evaluation Number 15, in JPL Publication 06-2, Jet Propulsion Laboratory, Pasadena, 2006.

Schade, G. W. and Goldstein, A. H.: Fluxes of oxygenated volatile organic compounds from a ponderosa pine plantation, J. Geophys. Res., 106, 3111–3123, 2001.

Schlessinger, W.: Biogeochemistry: an analysis of global change, 588 pp., Academic Press, San Diego, 1997.

Schrimpf, W., Lienaerts, K., Muller, K. P., Rudolph, J., Neubert, R., Schubler, W., and Levin, I.: Dry deposition of peroxyacetyl nitrate (PAN): Determination of its deposition velocity at night from measurements of the atmopsheric PAN and $^222$Radon concentration gradient, Geophys. Res. Lett., 23, 3599–3602, 1996.

Seaman, N. L., Stauffer, D. R., and Lariogibbs, A. M.: A Multiscale 4-Dimensional Data Assimilation System Applied in the San-Joaquin Valley During SARMAP .1. Modeling Design and Basic Performance-Characteristics, J. Appl. Meteorol., 34, 1739–1761, 1995.

Shepson, P. B., Bottenheim, J. W., Hastie, D. R., and Venkatram, A.: Determination of the Relative Ozone and PAN Deposition Velocities at Night, Geophys. Res. Lett., 19, 1121–1124, 1992.

Shepson, P. B., Mackay, E., and Muthuramu, K.: Henry's law constants and removal processes for several atmospheric beta-hydroxy alkyl nitrates, Environ. Sci. Technol., 30, 3618–3623, 1996.

Shu, Y. G. and Atkinson, R.: Rate Constants for the Gas-Phase Reactions of O3 with a Series of Terpenes and OH Radical Formation from the O3 Reactions with Sesquiterpenes at 296+/–2 K, Int. J. Chem. Kinet., 26, 1193–1205, 1994.

Sievering, H., Kelly, T., McConville, G., Seibold, C., and Turnipseed, A.: Nitric acid dry deposition to conifer forests: Niwot Ridge spruce-fir-pine study, Atmos. Eniviron., 35, 3851-3869, 2001.

Sparks, J. P., Monson, R. K., Sparks, K. L. and Lerdau, M.: Leaf uptake of nitrogen dioxide (NO$_2)$ in a tropical wet forest: implications for tropospheric chemistry, Oecologia, 127, 214–221, 2001.

Stroud, C., Makar, P., Karl, T., Guenther, A., Geron, C., Turnipseed, A., Nemitz, E., Baker, B., Potosnak, M., and Fuentes, J. D.: Role of canopy-scale photochemistry in modifying biogenic-atmosphere exchange of reactive terpene species: Results from the CELTIC field study, J. Geophys. Res., 110, D17303, doi:10.1029/2005JD005775, 2005.

Takemoto, B. K., Bytnerowicz, A., and Fenn, M. E.: Current and future effects of ozone and atmospheric nitrogen deposition on California's mixed conifer forests, Forest Ecology and Management, 144, 159–173, 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.: HOx budgets in a deciduous forest: Results from the PROPHET summer 1998 campaign, J. Geophys. Res., 106, 24 407–24 427, 2001.

Tarnay, L., Gertler, A. W., Blank, R. R., and Taylor Jr., G. E.: Preliminary measurements of summer nitric acid and ammonia concentrations in the Lake Tahoe Basin air-shed: implications for dry deposition of atmospheric nitrogen, Environmental Pollution, 113, 145–153, 2001.

Thornton, J., Wooldridge, P., Cohen, R., Martinez, M., Harder, H., Brune, W., Williams, E., Roberts, J., Fehsenfeld, F., Hall, S., Shetter, R., Wert, B., and Fried, A.: Ozone production rates as a function of NOx abundances and HOx production rates in the Nashville urban plume, J. Geophys. Res., 107(D12), 4146, doi:10.1029/JD000932, 2002.

100

Thornton, J. A., Wooldridge, P. J., and Cohen, R. C.: Atmospheric NO2: In situ laser-induced fluorescence detection at parts per trillion mixing ratios, Anal. Chem., 72, 528–539, 2000.

101

Thornton, J. A., Wooldridge, P. J., Cohen, R. C., Williams, E. J., Hereid, D. P., Fehsenfeld, F. C., Stutz, J., and Alicke, B.: Comparisons of in situ and long path measurements of NO2 in urban plumes, J. Geophys. Res., 108, 4496, doi:10.1029/2003JD003559, 2003.

102

Treves, K. and Rudich, Y.: The atmospheric fate of C3-C$_6$ hydroxyalkyl nitrates, J. Phys. Chem. A, 107, 7809–7817, 2003.

103

Tunved, P., Hansson, H. C., Kerminen, V. M., Strom, J., Dal Maso, M., Lihavainen, H., Viisanen, Y., Aalto, P. P., Komppula, M. and Kulmala, M.: High natural aerosol loading over boreal forests, Science, 312, 261–263, 2006.

104

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 (PANs) and NO$_y$ to a coniferous forest, J. Geophys. Res., 111, D09304, doi:10.1029/2005JD006631, 2006.

105

Tyndall, G. S., Cox, R. A., Granier, C., Lesclaux, R., Moortgat, G. K., Pilling, M. J., Ravishankara, A. R., and Wallington, T. J.: Atmospheric chemistry of small organic peroxy radicals, J. Geophys. Res., 106, 12 157–12 182, 2001.

106

Van Oss, R., Duyzer, J., and Wyers, P.: The influence of gas-to-particle conversion on measurements of ammonia exchange over forest, Atmos. Eniviron., 32, 465–471, 1998.

107

Wildt, J., Kley, D., Rockel, A., Rockel, P., and Segschneider, H. J.: Emission of NO from several higher plant species, J. Geophys. Res., 102, 5919–5927, 1997.

108

Williams, E. J., Hutchison, G. L., and Fehsenfeld, F. C.: NOx and N2O emissions from soil, Global Biogeochem. Cycles, 6, 351–388, 1992.

109

Zhou, X. L., Gao, H. L., He, Y., Huang, G., Bertman, S. B., Civerolo, K., and Schwab, J.: Nitric acid photolysis on surfaces in low-NOx environments: Significant atmospheric implications, Geophys. Res. Lett., 30, 2217, doi:10.1029/2003GL018620, 2003.