References

ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-11-5785-2011

Quantifying the magnitude of a missing hydroxyl radical source in a tropical rainforest

Whalley

L. K.

¹ ² Edwards

P. M.

¹ Furneaux

K. L.

¹ ⁷ Goddard

¹ Ingham

¹ ² Evans

M. J.

³ Stone

¹ Hopkins

J. R.

⁴ ⁵ Jones

C. E.

⁴ Karunaharan

⁶ Lee

J. D.

⁴ ⁵ Lewis

A. C.

⁴ ⁵ Monks

P. S.

⁶ Moller

S. J.

⁴ Heard

D. E.

¹ ²

School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK

National Centre for Atmospheric Science, University of Leeds, Leeds, LS2 9JT, UK

School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK

Chemistry Department, University of York, Heslington, YO10 5DD, UK

National Centre for Atmospheric Science, University of York, Heslington, YO10 5DD, UK

Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, UK

deceased

17 02 2011

11 2 5785 5809

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-discuss.net/11/5785/2011/acpd-11-5785-2011.html

The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/11/5785/2011/acpd-11-5785-2011.pdf

The lifetime of methane is controlled to a very large extent by the abundance of the OH radical. The tropics are a key region for methane removal, with oxidation in the lower tropical troposphere dominating the global methane removal budget (Bloss et al., 2005). In tropical forested environments where biogenic VOC emissions are high and NOx concentrations are low, OH concentrations are assumed to be low due to rapid reactions with sink species such as isoprene. New, simultaneous measurements of OH concentrations and OH reactivity, k'OH, in a Borneo rainforest are reported and show much higher OH than predicted, with mean peak concentrations of ~2.5×106 molecule cm−3 (10 min average) observed around solar noon. Whilst j(O1D) and humidity were high, low O3 concentrations limited the OH production from O3 photolysis. Measured OH reactivity was very high, peaking at a diurnal average of 29.1 ± 8.5 s−1, corresponding to an OH lifetime of only 34 ms. To maintain the observed OH concentration given the measured OH reactivity requires a rate of OH production approximately 10 times greater than calculated using all measured OH sources. A test of our current understanding of the chemistry within a tropical rainforest was made using a detailed zero-dimensional model to compare with measurements. The model over-predicted the observed HO2 concentrations and significantly under-predicted OH concentrations. Inclusion of an additional OH source formed as a recycled product of OH initiated isoprene oxidation improved the modelled OH agreement but only served to worsen the HO2 model/measurement agreement. To replicate levels of both OH and HO2, a process that recycles HO2 to OH is required; equivalent to the OH recycling effect of 0.74 ppbv of NO. This recycling step increases OH concentrations by 88% at noon and has wide implications, leading to much higher predicted OH over tropical forests, with a concomitant reduction in the CH4 lifetime and increase in the rate of VOC degradation.

References 1

Archibald, A. T., Cooke, M. C., Utembe, S. R., Shallcross, D. E., Derwent, R. G., and Jenkin, M. E.: Impacts of mechanistic changes on HOx formation and recycling in the oxidation of isoprene, Atmos. Chem. Phys., 10, 8097–8118, http://dx.doi.org/10.5194/acp-10-8097-2010doi:10.5194/acp-10-8097-2010, 2010.

Bloss, W. J., Evans, M. J., Lee, J. D., Sommariva, R., Heard, D. E., and Pilling, M. J.: The oxidative capacity of the troposphere: Coupling of field measurements of OH and a global chemistry transport model, Faraday Discuss, 130, 425–436, 2005.

%Bohn, B., Corlett, G. K., Gillmann, M., Sanghavi, S., Stange, G., Tensing, %E., Vrekoussis, M., Bloss, W. J., Clapp, L. J., Kortner, M., Dorn, H. P., %Monks, P. S., Platt, U., Plass-Dulmer, C., Mihalopoulos, N., Heard, D. E., %Clemitshaw, K. C., Meixner, F. X., Prevot, A. S. H., and Schmitt, R.: %Photolysis frequency measurement techniques: results of a comparison within %the ACCENT project, Atmos Chem Phys, 8, 5373-5391, 2008. Bohn, B., Corlett, G. K., Gillmann, M., Sanghavi, S., Stange, G., Tensing, E., Vrekoussis, M., Bloss, W. J., Clapp, L. J., Kortner, M., Dorn, H.-P., Monks, P. S., Platt, U., Plass-Dülmer, C., Mihalopoulos, N., Heard, D. E., Clemitshaw, K. C., Meixner, F. X., Prevot, A. S. H., and Schmitt, R.: Photolysis frequency measurement techniques: results of a comparison within the ACCENT project, Atmos. Chem. Phys., 8, 5373–5391, http://dx.doi.org/10.5194/acp-8-5373-2008doi:10.5194/acp-8-5373-2008, 2008.

Butler, T. M., Taraborrelli, D., Br�hl, 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., 8, 4529–4546, http://dx.doi.org/10.5194/acp-8-4529-2008doi:10.5194/acp-8-4529-2008, 2008.

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. Environ., 35, 4725–4737, 2001.

Da Silva, G., Graham, C., and Wang, Z.-F.: Unimolecular beta-hydroxyperoxy radical decompostion with OH recycling in the photochemical oxidation of isoprene, Environ. Sci Technol., 44, 250–256, 2010.

Dillon, T. J. and Crowley, J. N.: Direct detection of OH formation in the reactions of HO2 with CH3C(O)O2 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.

Edwards, P M., Whalley, L. K., Furneaux, K. L., Stone, D., and Evans,~M. J.: OH reactivity in a south east Asian tropical rainforest, Atmos Chem Phys Discuss, submitted, 2011.

Ehhalt, D. H. and Rohrer, F.: The tropospheric cycle of H2: a critical review, Tellus B, 61, 500–535, 2009.

Fleming, Z. L., Monks, P. S., Rickard, A. R., Heard, D. E., Bloss, W. J., Seakins, P. W., Still, T. J., Sommariva, R., Pilling, M. J., Morgan, R., Green, T. J., Brough, N., Mills, G. P., Penkett, S. A., Lewis, A. C., Lee, J. D., Saiz-Lopez, A., and Plane, J. M. C.: Peroxy radical chemistry and the control of ozone photochemistry at Mace Head, Ireland during the summer of 2002, Atmos. Chem. Phys., 6, 2193–2214, http://dx.doi.org/10.5194/acp-6-2193-2006doi:10.5194/acp-6-2193-2006, 2006.

Govaerts, Y M., Lattanzio, A., Taberner,~M., and Pinty, B.: Generating global surface albedo products from multiple geostationary satellites, Rem. Sens. Environ., 112, 2804–2816, 2008.

Hairer, E. and Wanner, G.: Solving Ordinary Differential Equations: Stiff and Differential-Algerbraic Problems, Berlin, 1991.

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.

Heard, D. E. and Pilling,~M. J.: Measurement of OH and HO2 in the troposphere, Chem. Rev., 103, 5163–5198, 2003.

Hewitt, C. N., Lee, J. D., MacKenzie, A. R., Barkley, M. P., Carslaw, N., Carver, G. D., Chappell, N. A., Coe, H., Collier, C., Commane, R., Davies, F., Davison, B., DiCarlo, P., Di Marco, C. F., Dorsey, J. R., Edwards, P. M., Evans, M. J., Fowler, D., Furneaux, K. L., Gallagher, M., Guenther, A., Heard, D. E., Helfter, C., Hopkins, J., Ingham, T., Irwin, M., Jones, C., Karunaharan, A., Langford, B., Lewis, A. C., Lim, S. F., MacDonald, S. M., Mahajan, A. S., Malpass, S., McFiggans, G., Mills, G., Misztal, P., Moller, S., Monks, P. S., Nemitz, E., Nicolas-Perea, V., Oetjen, H., Oram, D. E., Palmer, P. I., Phillips, G. J., Pike, R., Plane, J. M. C., Pugh, T., Pyle, J. A., Reeves, C. E., Robinson, N. H., Stewart, D., Stone, D., Whalley, L. K., and Yin, X.: Overview: oxidant and particle photochemical processes above a south-east Asian tropical rainforest (the OP3 project): introduction, rationale, location characteristics and tools, Atmos. Chem. Phys., 10, 169-199, http://dx.doi.org/10.5194/acp-10-169-2010doi:10.5194/acp-10-169-2010, 2010.

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, 2009.

Hopkins, J. R., Lewis, A. C., and Read, K. A.: A two-column method for long-term monitoring of non-methane hydrocarbons (NMHCs) and oxygenated volatile organic compounds (o-VOCs), J. Environ. Mon., 5, 8–13, 2003.

Ingham, T., Goddard, A., Whalley, L. K., Furneaux, K. L., Edwards, P. M., Seal, C. P., Self, D. E., Johnson, G. P., Read, K. A., Lee, J. D., and Heard, D. E.: A flow-tube based laser-induced fluorescence instrument to measure OH reactivity in the troposphere, Atmos. Meas. Tech., 2, 465–477, http://dx.doi.org/10.5194/amt-2-465-2009doi:10.5194/amt-2-465-2009, 2009.

Kubistin, D., Harder, H., Martinez, M., Rudolf, M., Sander, R., Bozem, H., Eerdekens, G., Fischer, H., Gurk, C., Kl�pfel, T., Königstedt, R., Parchatka, U., Schiller, C. L., Stickler, A., Taraborrelli, D., Williams, J., and Lelieveld, J.: Hydroxyl radicals in the tropical troposphere over the Suriname rainforest: comparison of measurements with the box model MECCA, Atmos. Chem. Phys., 10, 9705–9728, http://dx.doi.org/10.5194/acp-10-9705-2010doi:10.5194/acp-10-9705-2010, 2010.

Lelieveld, J., Peters, W., Dentener, F. J., and Krol,~M. C.: Stability of tropospheric hydroxyl chemistry, J. Geophys. Res. Atmos., 107, 4715–4732, 2002.

Lelieveld, J., Dentener, F. J., Peters, W., and Krol, M. C.: On the role of hydroxyl radicals in the self-cleansing capacity of the troposphere, Atmos. Chem. Phys., 4, 2337–2344, http://dx.doi.org/10.5194/acp-4-2337-2004doi:10.5194/acp-4-2337-2004, 2004.

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.

Madronich, S. and Flocke, S.: Handbook of Environmental Chemistry, edited by: Boule, P., Springer, 1–26, New York, USA, 1998.

%Malkin, T. L., Goddard, A., Heard, D. E., and Seakins, P. W.: Measurements %of OH and HO2 yields from the gas phase ozonolysis of isoprene, Atmos %Chem Phys, 10, 1441-1459, 2010. Malkin, T. L., Goddard, A., Heard, D. E., and Seakins, P. W.: Measurements of OH and HO2 yields from the gas phase ozonolysis of isoprene, Atmos. Chem. Phys., 10, 1441–1459, http://dx.doi.org/10.5194/acp-10-1441-2010doi:10.5194/acp-10-1441-2010, 2010.

Martin,~M. V., Honrath, R. E., Owen, R. C., Pfister, G., Fialho, P., and Barata, F.: Significant enhancements of nitrogen oxides, black carbon, and ozone in the North Atlantic lower free troposphere resulting from North American boreal wildfires, J. Geophys. Res. Atmos., 111, D23560, 2006.

Martinez, M., Harder, H., Kubistin, D., Rudolf, M., Bozem, H., Eerdekens, G., Fischer, H., Kl�pfel, T., Gurk, C., K�nigstedt, R., 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., 10, 3759–3773, http://dx.doi.org/10.5194/acp-10-3759-2010doi:10.5194/acp-10-3759-2010, 2010.

Monks, P. S.: Gas-phase radical chemistry in the troposphere, Chem. Soc. Rev., 34, 376–395, 2005.

Nguyen, T. L., Vereecken, L., and Peeters, J.: HOx Regeneration in the Oxidation of Isoprene III: Theoretical Study of the key Isomerisation of the Z-delta-hydroxy-peroxy Isoprene Radicals, Chem. Phys. Chem., 11, 3996–4001, 2010.

Novelli, P. C., Lang, P M., Masarie, K. A., Hurst, D. F., Myers, R., and Elkins, J. W.: Molecular hydrogen in the troposphere: Global distribution and budget, J. Geophys. Res. Atmos., 104, 30427–30444, 1999.

Paulot, F., Crounse, J. D., Kjaergaard, H. G., Kurten, A., St Clair, J M., Seinfeld, J. H., and Wennberg, P. O.: Unexpected Epoxide Formation in the Gas-Phase Photooxidation of Isoprene, Science, 325, 730–733, 2009.

Peeters, J., Nguyen, T. L., and Vereecken, L.: HOx radical regeneration in the oxidation of isoprene, Phys. Chem. Chem. Phys., 28, 5935–5939, 2009.

Pike, R. C., Lee, J. D., Young, P. J., Carver, G. D., Yang, X., Warwick, N., Moller, S., Misztal, P., Langford, B., Stewart, D., Reeves, C. E., Hewitt, C. N., and Pyle, J. A.: NOx and O3 above a tropical rainforest: an analysis with a global and box model, Atmos. Chem. Phys., 10, 10607–10620, http://dx.doi.org/10.5194/acp-10-10607-2010doi:10.5194/acp-10-10607-2010, 2010.

Pugh, T. A. M., MacKenzie, A. R., Hewitt, C. N., Langford, B., Edwards, P. M., Furneaux, K. L., Heard, D. E., Hopkins, J. R., Jones, C. E., Karunaharan, A., Lee, J., Mills, G., Misztal, P., Moller, S., Monks, P. S., and Whalley, L. K.: Simulating atmospheric composition over a South-East Asian tropical rainforest: performance of a chemistry box model, Atmos. Chem. Phys., 10, 279–298, http://dx.doi.org/10.5194/acp-10-279-2010doi:10.5194/acp-10-279-2010, 2010.

Pugh, T. A. M., MacKenzie, A. R., Langford, B., Nemitz, E., Misztal, P. K., and Hewitt, C. N.: The influence of small-scale variations in isoprene concentrations on atmospheric chemistry over a tropical rainforest, Atmos. Chem. Phys. Discuss., 10, 18197–18234, http://dx.doi.org/10.5194/acpd-10-18197-2010doi:10.5194/acpd-10-18197-2010, 2010.

Ren, X. R., Olson, J. R., Crawford, J. H., Brune, W. H., Mao, J. Q., 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. O., Singh, H. B., Blake, D. R., and Shetter, R. E.: HOx chemistry during INTEX-A 2004: Observation, model calculation, and comparison with previous studies, J. Geophys. Res. Atmos., 113, D05310, 2008.

Salisbury, G., Rickard, A. R., Monks, P. S., Allan, B. J., Bauguitte, S., Penkett, S. A., Carslaw, N., Lewis, A. C., Creasey, D. J., Heard, D. E., Jacobs, P. J., and Lee, J. D.: Production of peroxy radicals at night via reactions of ozone and the nitrate radical in the marine boundary layer, J. Geophys. Res. Atmos., 106, 12669–12687, 2001.

%Stavrakou, T., Peeters, J., and Müller, J. F.: Improved global modelling %of HOx recycling in isoprene oxidation: evaluation against the %GABRIEL and INTEX-A aircraft campaign measurements, Atmos Chem Phys, 10, %9863-9878, 2010. Stavrakou, T., Peeters, J., and Müller, J.-F.: Improved global modelling of HOx recycling in isoprene oxidation: evaluation against the GABRIEL and INTEX-A aircraft campaign measurements, Atmos. Chem. Phys., 10, 9863-9878, http://dx.doi.org/10.5194/acp-10-9863-2010doi:10.5194/acp-10-9863-2010, 2010.

%Stone, D., Evans,~M. J., Commane, R., Ingham, T., Floquet, C. F. A., %McQuaid, J. B., Brookes, D M., Monks, P. S., Purvis, R., Hamilton, J. F., %Hopkins, J., Lee, J., Lewis, A. C., Stewart, D., Murphy, J. G., Mills, G., %Oram, D., Reeves, C. E., and Heard, D. E.: HOx observations over West %Africa during AMMA: impact of isoprene and NOx, Atmos Chem Phys, 10, %9415-9429, 2010. Stone, D., Evans, M. J., Commane, R., Ingham, T., Floquet, C. F. A., McQuaid, J. B., Brookes, D. M., Monks, P. S., Purvis, R., Hamilton, J. F., Hopkins, J., Lee, J., Lewis, A. C., Stewart, D., Murphy, J. G., Mills, G., Oram, D., Reeves, C. E., and Heard, D. E.: HOx observations over West Africa during AMMA: impact of isoprene and NOx, Atmos. Chem. Phys., 10, 9415–9429, http://dx.doi.org/10.5194/acp-10-9415-2010doi:10.5194/acp-10-9415-2010, 2010.

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. Atmos., 106, 24407–24427, 2001.

Thornton, J. A., Wooldridge, P. J., Cohen, R. C., Martinez,~M., Harder, H., Brune, W. H., Williams, E. J., Roberts, J M., Fehsenfeld, F. C., Hall, S. R., Shetter, R. E., Wert, B. P., and Fried, A.: Ozone production rates as a function of NOx abundances and HOx production rates in the Nashville urban plume, J. Geophys. Res. Atmos., 107, 4146–4153, 2002.

%Whalley, L. K., Furneaux, K. L., Goddard, A., Lee, J. D., Mahajan, A., %Oetjen, H., Read, K. A., Kaaden, N., Carpenter, L. J., Lewis, A. C., Plane, %J M. C., Saltzman, E. S., Wiedensohler, A., and Heard, D. E.: The chemistry %of OH and HO2 radicals in the boundary layer over the tropical Atlantic %Ocean, Atmos Chem Phys, 10, 1555-1576, 2010. Whalley, L. K., Furneaux, K. L., Goddard, A., Lee, J. D., Mahajan, A., Oetjen, H., Read, K. A., Kaaden, N., Carpenter, L. J., Lewis, A. C., Plane, J. M. C., Saltzman, E. S., Wiedensohler, A., and Heard, D. E.: The chemistry of OH and HO2 radicals in the boundary layer over the tropical Atlantic Ocean, Atmos. Chem. Phys., 10, 1555–1576, http://dx.doi.org/10.5194/acp-10-1555-2010doi:10.5194/acp-10-1555-2010, 2010.

Wild, O., Law, K. S., McKenna, D. S., Bandy, B. J., Penkett, S. A., and Pyle, J. A.: Photochemical trajectory modeling studies of the North Atlantic region during August 1993, J. Geophys. Res.-Atmos., 101, 29269–29288, 1996.