Multimodel ensemble simulations of present-day and near-future tropospheric ozone

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Read Full Article (file size: 2289534 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, D08301, doi:10.1029/2005JD006338, 2006 Multimodel ensemble simulations of present-day and near-future tropospheric ozone D. S. Stevenson School of Geosciences, University of Edinburgh, Edinburgh, UK F. J. Dentener Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy M. G. Schultz Max Planck Institute for Meteorology, Hamburg, Germany K. Ellingsen Department of Geosciences, University of Oslo, Oslo, Norway T. P. C. van Noije Atmospheric Composition Research, Royal Netherlands Meteorological Institute, De Bilt, Netherlands O. Wild Frontier Research Center for Global Change, Japan Marine Science and Technology Center, Yokohama, Japan G. Zeng Centre for Atmospheric Science, University of Cambridge, Cambridge, UK M. Amann International Institute for Applied Systems Analysis, Laxenburg, Austria C. S. Atherton Atmospheric Science Division, Lawrence Livermore National Laboratory, Livermore, California, USA N. Bell NASA Goddard Institute for Space Studies, New York, New York, USA D. J. Bergmann Atmospheric Science Division, Lawrence Livermore National Laboratory, Livermore, California, USA I. Bey Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland T. Butler Max Planck Institute for Chemistry, Mainz, Germany J. Cofala International Institute for Applied Systems Analysis, Laxenburg, Austria W. J. Collins Hadley Centre for Climate Prediction and Research, Met Office, Exeter, UK R. G. Derwent rdscientific, Newbury, Berkshire, UK R. M. Doherty School of Geosciences, University of Edinburgh, Edinburgh, UK J. Drevet Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland H. J. Eskes Atmospheric Composition Research, Royal Netherlands Meteorological Institute, De Bilt, Netherlands A. M. Fiore Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, New Jersey, USA M. Gauss Department of Geosciences, University of Oslo, Oslo, Norway D. A. Hauglustaine Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France L. W. Horowitz Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, New Jersey, USA I. S. A. Isaksen Department of Geosciences, University of Oslo, Oslo, Norway M. C. Krol Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy J.-F. Lamarque Atmospheric Chemistry Division, National Center of Atmospheric Research, Boulder, Colorado, USA M. G. Lawrence Max Planck Institute for Chemistry, Mainz, Germany V. Montanaro Dipartimento di Fisica, Università L'Aquila, L'Aquila, Italy J.-F. Müller Belgian Institute for Space Aeronomy, Brussels, Belgium G. Pitari Dipartimento di Fisica, Università L'Aquila, L'Aquila, Italy M. J. Prather Department of Earth System Science, University of California, Irvine, California, USA J. A. Pyle Centre for Atmospheric Science, University of Cambridge, Cambridge, UK S. Rast Max Planck Institute for Meteorology, Hamburg, Germany J. M. Rodriguez University of Miami, Rosentiel School of Marine and Atmospheric Sciences, Miami, Florida, USA NASA Goddard Space Flight Center, Greenbelt, Maryland, USA M. G. Sanderson Hadley Centre for Climate Prediction and Research, Met Office, Exeter, UK N. H. Savage Centre for Atmospheric Science, University of Cambridge, Cambridge, UK D. T. Shindell NASA Goddard Institute for Space Studies, New York, New York, USA S. E. Strahan University of Miami, Rosentiel School of Marine and Atmospheric Sciences, Miami, Florida, USA K. Sudo Frontier Research Center for Global Change, Japan Marine Science and Technology Center, Yokohama, Japan S. Szopa Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France Abstract Global tropospheric ozone distributions, budgets, and radiative forcings from an ensemble of 26 state-of-the-art atmospheric chemistry models have been intercompared and synthesized as part of a wider study into both the air quality and climate roles of ozone. Results from three 2030 emissions scenarios, broadly representing “optimistic,” “likely,” and “pessimistic” options, are compared to a base year 2000 simulation. This base case realistically represents the current global distribution of tropospheric ozone. A further set of simulations considers the influence of climate change over the same time period by forcing the central emissions scenario with a surface warming of around 0.7K. The use of a large multimodel ensemble allows us to identify key areas of uncertainty and improves the robustness of the results. Ensemble mean changes in tropospheric ozone burden between 2000 and 2030 for the 3 scenarios range from a 5% decrease, through a 6% increase, to a 15% increase. The intermodel uncertainty (±1 standard deviation) associated with these values is about ±25%. Model outliers have no significant influence on the ensemble mean results. Combining ozone and methane changes, the three scenarios produce radiative forcings of −50, 180, and 300 mW m⁻², compared to a CO₂ forcing over the same time period of 800–1100 mW m⁻². These values indicate the importance of air pollution emissions in short- to medium-term climate forcing and the potential for stringent/lax control measures to improve/worsen future climate forcing. The model sensitivity of ozone to imposed climate change varies between models but modulates zonal mean mixing ratios by ±5 ppbv via a variety of feedback mechanisms, in particular those involving water vapor and stratosphere-troposphere exchange. This level of climate change also reduces the methane lifetime by around 4%. The ensemble mean year 2000 tropospheric ozone budget indicates chemical production, chemical destruction, dry deposition and stratospheric input fluxes of 5100, 4650, 1000, and 550 Tg(O₃) yr⁻¹, respectively. These values are significantly different to the mean budget documented by the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR). The mean ozone burden (340 Tg(O₃)) is 10% larger than the IPCC TAR estimate, while the mean ozone lifetime (22 days) is 10% shorter. Results from individual models show a correlation between ozone burden and lifetime, and each model's ozone burden and lifetime respond in similar ways across the emissions scenarios. The response to climate change is much less consistent. Models show more variability in the tropics compared to midlatitudes. Some of the most uncertain areas of the models include treatments of deep tropical convection, including lightning NO_x production; isoprene emissions from vegetation and isoprene's degradation chemistry; stratosphere-troposphere exchange; biomass burning; and water vapor concentrations. Received 9 June 2005; accepted 19 December 2005; published 26 April 2006. Keywords: intercomparison; modeling; tropospheric ozone. Index Terms: 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry; 0368 Atmospheric Composition and Structure: Troposphere: constituent transport and chemistry; 0345 Atmospheric Composition and Structure: Pollution: urban and regional (0305, 0478, 4251); 0322 Atmospheric Composition and Structure: Constituent sources and sinks. Read Full Article (file size: 2289534 bytes) Cited by Citation: Stevenson, D. S., et al. (2006), Multimodel ensemble simulations of present-day and near-future tropospheric ozone, J. Geophys. Res., 111, D08301, doi:10.1029/2005JD006338. Copyright 2006 by the American Geophysical Union.

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