ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-10-7117-2010 Effects of climate-induced changes in isoprene emissions after the eruption of Mount Pinatubo Telford P. J. 1 Lathière J. 2 3 4 Abraham N. L. 1 Archibald A. T. 1 Braesicke P. 1 Johnson C. E. 5 Morgenstern O. 1 6 O'Connor F. M. 5 Pike R. C. 1 Wild O. 3 Young P. J. 1 7 Beerling D. J. 2 Hewitt C. N. 3 Pyle J. 1 Centre for Atmospheric Science, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK Department of Plant and Animal Sciences, University of Sheffield, Sheffield, UK Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK now at Laboratoire des Sciences du Climat et de l'Environment, Gif sur Yvette, France Met Office Hadley Centre, Exeter, UK now at: National Institute of Water and Atmospheric Research, Lauder, New Zealand now at: NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA 03 08 2010 10 15 7117 7125 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/10/7117/2010/acp-10-7117-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/10/7117/2010/acp-10-7117-2010.pdf

In the 1990s the rates of increase of greenhouse gas concentrations, most notably of methane, were observed to change, for reasons that have yet to be fully determined. This period included the eruption of Mt. Pinatubo and an El Niño warm event, both of which affect biogeochemical processes, by changes in temperature, precipitation and radiation. We examine the impact of these changes in climate on global isoprene emissions and the effect these climate dependent emissions have on the hydroxy radical, OH, the dominant sink for methane. We model a reduction of isoprene emissions in the early 1990s, with a maximum decrease of 40 Tg(C)/yr in late 1992 and early 1993, a change of 9%. This reduction is caused by the cooler, drier conditions following the eruption of Mt. Pinatubo. Isoprene emissions are reduced both directly, by changes in temperature and a soil moisture dependent suppression factor, and indirectly, through reductions in the total biomass. The reduction in isoprene emissions causes increases of tropospheric OH which lead to an increased sink for methane of up to 5 Tg(CH<sub>4</sub>)/year, comparable to estimated source changes over the time period studied. There remain many uncertainties in the emission and oxidation of isoprene which may affect the exact size of this effect, but its magnitude is large enough that it should remain important.

 References Archibald, A., Jenkin, M., and Shallcross, D.: An isoprene mechanism intercomparison, Atmos. Env., \doi10.1016/j.atmosenv.2009.09.016, in press, 2009. Barkley, M., Palmer, P., Kuhn, U., Kesselmeier, J., Chance, K., Kurosu, T., Martin, R., Helmig, D., and Guenther, A.: Net ecosystem flux of isoprene over tropical South America inferred from Global Ozone Monitoring Experiment (GOME) observation of HCHO columns, J. Geophys. Res., 113, D20304, \doi10.1029/2008JD009863, 2008. Beerling, D., Woodward, F., Lomas, M., and Jenkins, A.: Testing the responses of a dynamic global vegetation model to environmental change: a comparison of observations and predictions, Global Ecol. Biogeogr. Lett., 6, 439–50, 1997. Beerling, D J. and Woodward, F I.: Vegetation and the terrestrial carbon cycle. Modelling the first 400 million years, Cambridge University Press, 2001. Bekki, S., Law, K., and Pyle, J.: Effect of ozone depletion on atmospheric CH<sub>4</sub> and CO concentrations, Nature, 371, 595–597, 1994. Bousquet, P., Hauglustaine, D A., Peylin, P., Carouge, C., and Ciais, P.: Two decades of OH variability as inferred by an inversion of atmospheric transport and chemistry of methyl chloroform, Atmos. Chem. Phys., 5, 2635–2656, doi:10.5194/acp-5-2635-2005, 2005. Bousquet, P., Ciais, P., Miller, J B., Dlugokencky, E J., Hauglustaine, D A., Prigent, C., der Werf, G. R V., Peylin, P., Brunke, E.-G., Carouge, C., Langenfelds, R L., Lathière, J., Papa, F., Ramonet, M., Schmidt, M., Steele, L P., Tyler, S C., and White, J.: Contribution of anthropogenic and natural sources to atmospheric methane variability, Nature, 443, 439–443, 2006. Claeys, M., Graham, B., Vas, G., Wang, W., Vermeylen, R., Pashynka, V., Cafmeyer, J., Guyon, P., Andreae, M., Artaxo, P., and Maenhaut, W.: Formation of Secondary Organic Aerosols Through Photooxidation of Isoprene, Science, 303, \doi10.1126/science.1092805, 2004. \bibitem[da~Silva et~al.(2010) da~Silva, Graham and Wang] dasilva10 da~Silva, G., Graham, C. and Wang, Z.-F.: Unimolecular β-Hydroxyperoxy Radical Decomposition with \oh recycling in the Photochemical Oxidation of Isoprene, Environ. Sci. Technol., 44, 250–256, 2010 Dalsøren, S. and Isaksen, I.: CTM study of changes in tropospheric hydroxyl 1–7, 2006. Denman, K., Brasseuer, G., Chidthaisong, A., Ciais, P., Cox, P., Dickinson, R., Hauglustaine, D., Heinze, C., Holland, E., Jacob, D., Lohmann, U., Ramachandran, S., de~Silva, P., Wofsy, S., and X Zhang, L.: Climate Change 2007: The Physical Science Basis, chap. Couplings Between Changes in the Climate System and Biogeochemistry, Cambridge University Press, 499–587, 2007. Dlugokencky, E., Houweling, S., Bruhwiler, L., Masarie, K., Lang, P., Miller, J., and Tans, P.: Atmospheric methane levels off: Temporary pause or a new steady-state?, Geophys. Res. Lett., 30, 1992, doi:10.1029/2003GL018126, 2003. Eyers, C., Addleton, D., Atkinson, K., Broomhead, M., Christou, R., Elliff, T., Falk, R., Gee, I., Lee, D., Marizy, C., Michot, S., Middel, J., Newton, P., Norman, P., Plohr, M., Raper, D., and Stanciou, N.: AERO2K global aviation emissions inventories for 2002 and 2025, Tech. Rep. QinetiQ/04/01113, Qinetiq, 2004. Gedney, N., Cox, P., and Huntingford, C.: Climate feedback from wetland methane emissions, Geophys. Res. Lett., 31, L20503, doi:10.1029/2004GL020919, 2004. Giannakopoulos, C., Chipperfield, M., Law, K., and Pyle, J.: Validation and intercomparison of wet and dry deposition schemes using Pb-210 in a global three-dimensional off-line chemical transport model, J. Geophys. Res., 104, 23761–23784, 1999. Guenther, A., Karl, T., Harley, P., Wiedinmyer, C., Palmer, P., and Geron, C.: Estimates of global terrestrial isoprene emissions using MEGAN (Model of Emissions of Gases and Aerosols from Nature), Atmos. Chem. Phys., 6, 3181–3210, 2006. Johnson, C., Stevenson, D., Collins, W., and Derwent, R.: Interannual variability in methane growth rate simulated with a coupled Ocean-Atmosphere-Chemistry model, Geophys. Res. Lett., 29, 1903, doi:10.1029/2002GL015269, 2002. Krol, M. and Lelieveld, J.: Can the variability in tropospheric OH be deduced from measurements of 1,1,1-trichloroethane (methyl chloroform)?, J. Geophys. Res., 108, 4125, doi:10.1029/2002JD002423, 2003. Lathière, J., Hauglustaine, D. A., Friend, A. D., De Noblet-Ducoudré, N., Viovy, N., and Folberth, G. A.: Impact of climate variability and land use changes on global biogenic volatile organic compound emissions, Atmos. Chem. Phys., 6, 2129–2146, doi:10.5194/acp-6-2129-2006, 2006. Lathière, J., Hewitt, N., and Beerling, D.: Sensitivity of isoprene emissions from the terrestrial biosphere to 20th century changes in atmospheric CO2 concentration, climate and land use, Global Biogeochemical Cycles, 24, GB1004, doi:10.1029/2009GB003548, 2010. Law, K. and Pyle, J.: Modeling trace gas budgets in the troposphere.1. ozone and odd nitrogen, J. Geophys. Res., 98, 18377–18400, 1993a. Law, K. and Pyle, J.: Modeling trace gas budgets in the troposphere 2. CH<sub>4</sub> and CO, J. Geophys. Res., 98, 18,401–18,412, 1993b. Law, K., Plantevin, P., Shallcross, D., Rogers, H., Pyle, J., Grouhel, C., Thouret, V., and Marenco, A.: Evaluation of modeled O<sub>3</sub> using Measurement of Ozone by Airbus In-Service Aircraft (MOZAIC) data, J. Geophys. Res., 103, 25721–25737, 1998. Lelieveld, J., Crutzen, P., and Dentener, F.: Changing concentration, lifetime and climate forcing of atmospheric methane, Tellus B – Chem. Phys. Meteorol., 50, 128–150, 1998. Lelieveld, J., Butler, T., Crowley, J., Dillon, T., Fischer, H. L. G., Harder, H., Lawrence, M., Martinez, M., Taraborrelli, D., and Williams, J.: Atmospheric oxidation capacity sustained by a tropical forest., Nature, 452, 737–740, 2008. McCormick, M., Thomason, L., and Trepte, C.: Atmospheric Effects of the Mount Pinatubo Eruption, Nature, 373, 399–405, 1995. Milton, S. and Dean, W.: Disturbance, drought and dynamics of desert dune grassland, South Africa, Plant Ecol., 150, 37–51, 2000. Morgenstern, O., Braesicke, P., O'Connor, F. M., Bushell, A. C., Johnson, C. E., Osprey, S. M., and Pyle, J. A.: Evaluation of the new UKCA climate-composition model – Part 1: The stratosphere, Geosci. Model Dev., 2, 43–57, doi:10.5194/gmd-2-43-2009, 2009. Müller, J.-F., Stavrakou, T., Wallens, S., Smedt, I D., Roozendael, M V., Potosnak, M J., Rinne, J., Munger, B., Goldstein, A., and Guenther, A B.: Global isoprene emissions estimated using MEGAN, ECMWF analyses and a detailed canopy environment model, Atmos. Chem. Phys., 8, 1329–1341, doi:10.5194/acp-8-1329-2008, 2008. O'Connor, F., Johnson, C., Morgenstern, O., and Collins, W J.: Interactions between tropospheric chemistry and climate model temperature and humidity biases, Geophys. Res. Lett, 36, L16801, \doidoi:10.1029/2009GL039152, 2009. O'Connor, F., Johnson, C., Morgenstern, O., Sanderson, M., Young, P., Collins, W., and J Pyle, J A.: Evaluation of the new UKCA climate-composition model – Part 2: The Troposphere, Geosci. Model Dev. Discuss., in preparation, 2010. Paulot, F., Crounse, J., Kjaergaard, H., Kürten, A., St Clair, J., Seinfeld, J., and Wennberg, P.: Unexpected Epoxide Formation in the Gas-Phase Photooxidation of Isoprene, Science, 325, 730–733, 2009. Peeters, J. , Nguyen, T. and Vereecken, L.:HO$_x$ radical regeneration in the oxidation of isoprene, Phys. Chem. Chem. Phys., 11, 5935–5939, \doi10.1039/b908511d, 2009. Pike, R. C., Lee, J. D., Young, P. J., Moller, S., Carver, G. D., Yang, X., Misztal, P., Langford, B., Stewart, D., Reeves, C. E., Hewitt, C. N., and Pyle, J. A.: Can a global model chemical mechanism reproduce NO, NO<sub>2</sub>, and O<sub>3</sub> measurements above a tropical rainforest?, Atmos. Chem. Phys. Discuss., 9, 27611–27648, doi:10.5194/acpd-9-27611-2009, 2009. Pöschl, U., von Kuhlmann, R., Poisson, N., and Crutzen, P.: Development and intercomparison of condensed isoprene oxidation mechanisms for global atmospheric modelling, J. Atmos. Chem., 37, 29–52, 2000. Price, C. and Rind, D.: Modelling global lightning distributions in a general circulation model, Mon. Weath. Rev., 122, 1930–1939, 1994. Qian, H., Joseph, R., and Zeng, N.: Response of the terrestrial carbon cycle to the El Niño-Southern Oscillation, Tellus B – Chem. Phys. Meteorol., 60, 537–550, 2008. Rayner, A., Rayner, N., Parker, D., Horton, E., Folland, C., Alexander, L., Rowell, D., Kent, E., and Kaplan, A.: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century, J. Geophys. Res., 108D, 4407, doi:10.1029/2002JD002670, 2003. Sanderson, M., Jones, C., Collins, W., Johnson, C., and Derwent, R.: Effect of climate change on isoprene emissions and surface ozone levels, Geophys. Res. Lett, 30, 1936, \doidoi:10.1029/2003GL017642., 2003. Sharkey, T., Wiberley, A., and Donohue, A.: Isoprene Emission from Plants: Why and How, Ann. Botany, 10, 1–14, \doi10.1093/aob/mcm240, 2007. Stevenson, D., Dentener, F., Schultz, M., Ellingsen, K., van Noije, T., Wild, O., Zeng, G., Amann, M., Atherton, C., Bell, N., Bergmann, D., Bey, I., Butler, T., Cofala, J., Collins, W., Derwent, R., Doherty, R., Drevet, J., Eskes, H., Fiore, A., Gauss, M., Hauglustaine, D., Horowitz, L., Isaksen, I., Krol, M., Lamarque, J.-F., Lawrence, M., Montanaro, V., ller, J.-F M., Pitari, G., Prather, M., Pyle, J., Rast, S., Rodriguez, J., Sanderson, M., Savage, N., Shindell, D., Strahan, S., Sudo, K., and Szopa, S.: Multimodel ensemble simulations of present-day and near-future tropospheric ozone, J. Geophys. Res., 111, D08301, \doi10.1029/2005JD006338, 2006. Telford, P. J., Braesicke, P., Morgenstern, O., and Pyle, J. A.: Technical Note: Description and assessment of a nudged version of the new dynamics Unified Model, Atmos. Chem. Phys., 8, 1701–1712, doi:10.5194/acp-8-1701-2008, 2008. Telford, P., Braesicke, P., Morgenstern, O., and Pyle, J.: Reassessment of Causes of Ozone Column Variability following the Eruption of Mount Pinatubo using a nudged CCM, Atmos. Chem. Phys., 9, 4251–4260, doi:10.5194/acp-9-4251-2009, 2009. Tian, H., Melillo, J., Kicklighter, D., McGuire, A., Helfrich III, J., Moore III, B., and Vörösmarty, C.: Effect of interannual climate variability on carbon storage in Amazonian ecosystems, Nature, 396, 664–667, 1998. Trenberth, K. and Dai, A.: Effects of Mount Pinatubo volcanic eruption on the hydrological cycle as an analog of geoengineering, Geophys. Res. Lett., 34, 15702, \doi10.1029/2007GL030524, 2007. Uppala, S., Kallberg, P., Simmons, A., Andrae, U., Da~Costa~Bechtold, V., Fiorino, M., Gibson, J., Haseler, J., Hernandez, A., Kelly, G., Li, X., Onogi, K., Saarinen, S., Sokka, N., Allan, R., Andersson, E., Arpe, K., Balmaseda, M., Beljaars, A., van~de Berg, L., Bidlot, J., Bormann, N., Caires, S., Chevallier, F., Dethof, A., Dragosavac, M., Fisher, M., Fuentes, M., Hagemann, S., Holm, E., Hoskins, B., Isaksen, L., Janssen, P., Jenne, R., McNally, A., Mahfouf, J.-F., Morcrette, J.-J., .Rayner, N., Saunders, R., Simon, P., Sterl, A., Trenberth, K., Untch, A., Vasiljevic, D., Viterbo, P., and Woollen, J.: The ERA-40 re-analysis, Q. J. Roy. Meteor. Soc., 131, 2961–3012, 2005. Wang, J., Logan, J., McElroy, M., Duncan, B., Megretskaia, I., and Yantosca, R.: A 3-D model analysis of the slowdown and interannual variability in the methane growth rate from 1988–1997, Global Biogeochem. Cy., 18, GB3011, doi:10.1029/2003GB002180, 2004. Warwick, N., Bekki, S., Law, K., Nisbet, E., and Pyle, J.: The impact of meteorology on the interannual growth rate of atmospheric methane, Geophys. Res. Lett., 29, 1947, doi:10.1029/2002GL015282, 2002. Wolter, K. and Timlin, M.: Monitoring ENSO in COADS with a seasonally adjusted principal component index, in: Proc. of the 17th Climate Diagnostics Workshop, Norman, OK, NOAA/N MC/CAC, NSSL, Oklahoma Clim. Survey, CIMMS and the School of Meteor., Univ. of Oklahoma, 52–57, 1993. Young, P. J., Arneth, A., Schurgers, G., Zeng, G., and Pyle, J. A.: The CO<sub>2</sub> inhibition of terrestrial isoprene emission significantly affects future ozone projections, Atmos. Chem. Phys., 9, 2793–2803, doi:10.5194/acp-9-2793-2009, 2009. Zeng, G. and Pyle, J A.: Changes in tropospheric ozone between 2000 and 2100 modeled in a chemistry-climate model, Geophys. Res. Lett., 30, 1392, doi:10.1029/2002GL016708, 2003.