Skip to main content
Article thumbnail
Location of Repository

Modelling the global tropospheric ozone budget : exploring the variability in current models.

By Oliver Wild

Abstract

What are the largest uncertainties in modelling ozone in the troposphere, and how do they affect the calculated ozone budget? Published chemistry-transport model studies of tropospheric ozone differ significantly in their conclusions regarding the importance of the key processes controlling the ozone budget: influx from the stratosphere, chemical processing and surface deposition. This study surveys ozone budgets from previous studies and demonstrates that about two thirds of the increase in ozone production seen between early assessments and more recent model intercomparisons can be accounted for by increased precursor emissions. Model studies using recent estimates of emissions compare better with ozonesonde measurements than studies using older data, and the tropospheric burden of ozone is closer to that derived here from measurement climatologies, 335±10 Tg. However, differences between individual model studies remain large and cannot be explained by surface precursor emissions alone; cross-tropopause transport, wet and dry deposition, humidity, and lightning also make large contributions. The importance of these processes is examined here using a chemistry-transport model to investigate the sensitivity of the calculated ozone budget to different assumptions about emissions, physical processes, meteorology and model resolution. The budget is particularly sensitive to the magnitude and location of lightning NOx emissions, which remain poorly constrained; the 3–8 TgN/yr range in recent model studies may account for a 10% difference in tropospheric ozone burden and a 1.4 year difference in CH4 lifetime. Differences in humidity and dry deposition account for some of the variability in ozone abundance and loss seen in previous studies, with smaller contributions from wet deposition and stratospheric influx. At coarse model resolutions stratospheric influx is systematically overestimated and dry deposition is underestimated; these differences are 5–8% at the 300–600 km grid-scales investigated here, similar in magnitude to the changes induced by interannual variability in meteorology. However, a large proportion of the variability between models remains unexplained, suggesting that differences in chemical mechanisms and dynamical schemes have a large impact on the calculated ozone budget, and these should be the target of future model intercomparisons

Year: 2007
OAI identifier: oai:eprints.lancs.ac.uk:27964
Provided by: Lancaster E-Prints

Suggested articles

Citations

  1. (2007). 2660 O. Wild: Sensitivities in modelling global tropospheric ozone
  2. (1995). A 4-Dimensional Ozone Climatology for UGAMP Models,
  3. (1995). A global model of natural volatile organic compound emissions,
  4. (2003). A global simulation of tropospheric ozone and related tracers: Description and evaluation of MOZART, version 2,
  5. (2003). A model for studies of tropospheric ozone and nonmethane hydrocarbons: Model description and ozone results,
  6. (1992). A simple lightning parameterization for calculating global lightning distributions,
  7. (1996). A threedimensional simulation of the ozone annual cycle using winds from a data assimilation system,
  8. (2004). A.: Interactive chemistry in the Laboratoire de M´ et´ eorologie Dynamique general circulation model: Description and background tropospheric chemistry evaluation,
  9. (2004). A.: Interactive chemistry in the Laboratoire de Me´te´orologie Dynamique general circulation model: Description and background tropospheric chemistry evaluation,
  10. (1998). A.: MOZART, a global chemical transport model for ozone and related chemical tracers: 2. Model results and evaluation,
  11. (2001). Altitude dependence of tropospheric ozone over the Northern Hemisphere during 1996, simulated with a chemistry-general circulation model at two different resolutions,
  12. (1999). An analysis of ozonesonde data for the troposphere: Recommendations for testing 3-D models, and development of a gridded climatology for tropospheric ozone,
  13. (1994). An estimate of the flux of stratospheric reactive nitrogen and ozone into the troposphere,
  14. (1998). An ozone climatology based on ozonesonde and satellite measurements,
  15. (2001). Atmospheric Chemistry and Greenhouse Gases, in Climate Change 2001: The Scientific Basis, edited by:
  16. (2003). Carbon emissions from fires in tropical and subtropical ecosystems,
  17. (2002). CHASER: A global chemical model of the troposphere 2. Model results and evaluation,
  18. (2001). Chemistryclimate interactions in the Goddard Institute for Space Studies general circulation model. 1. Tropospheric chemistry model description and evaluation,
  19. (1998). Comparison of modelled ozone distributions with sonde and satellite observations,
  20. (1990). Convection links biomass burning to increased tropical ozone: However, models will tend to overpredict O3,
  21. (1996). Description of EDGAR Version 2.0, RIVM/TNO
  22. (2000). Development and intercomparison of condensed isoprene oxidation mechanisms for global atmospheric modeling,
  23. (1991). Development of a two-dimensional global tropospheric model: Model chemistry,
  24. (1995). Distribution and budget of O3 in the troposphere calculated with a chemistry general circulation model,
  25. (2003). Effect of clouds on photolysis and oxidants in the troposphere,
  26. (1998). Effects of 1997–1998 El Ni˜ no on tropospheric ozone and water vapor,
  27. (1998). Effects of 1997–1998 El Nin˜o on tropospheric ozone and water vapor,
  28. (2003). et al.: Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998–2000 tropical ozone climatology 1. Comparison with Total Ozone Mapping Spectrometer (TOMS) and groundbased measurements,
  29. (2003). etal.: Aglobalsimulation of tropospheric ozone and related tracers: Description and evaluation of MOZART, version 2,
  30. (2000). Excitation of the primary tropospheric chemical mode in a global 3-D model,
  31. (2000). Fast-J: Accurate simulation of in- and below-cloud photolysis in tropospheric chemical models,
  32. (1997). Global distribution based on lightning physics,
  33. (2001). Global emissions sources and sinks, in: The Climate System, edited by:
  34. (2001). Global modelling of tropospheric chemistry with assimilated meteorology: Model description and evaluation,
  35. (1998). Global simulation of tropospheric O3–NOx–hydrocarbon chemistry. 2. Model evaluation and global ozone budget,
  36. (2001). Global simulation of tropospheric ozone using the University of Maryland Chemical Transport Model (UMD-CTM): 1. Model description and evaluation,
  37. (2006). Global tropospheric ozone modelling: Quantifying errors due to grid resolution,
  38. (1995). IMAGES: A three-dimensional chemical transport model of the global troposphere,
  39. (2006). Impact of meteorology and emissions on methane trends, 1990–2004,
  40. (2004). IMPACT, the LLNL 3-D global atmospheric chemical transport model for the combined troposphere and stratosphere: Model description and analysis of ozone and other trace gases,
  41. (1996). Impacts of increased anthropogenic emissions in Asia on tropospheric ozone and climate. A global 3-D model study,
  42. (1996). Impacts of increased anthropogenic emissions in Asia on tropospheric ozone and climate. A global 3-D model study, Tellus,
  43. (2004). Implications of the enhanced Brewer-Dobson circulation in European Centre for Medium-Range Weather Forecasts reanalysis ERA-40 for the stratosphere- troposphere exchange of ozone in global chemistry transport models,
  44. (2005). Influence of convective transport on tropospheric ozone and its precursors in a chemistry-climate model,
  45. (2005). Influence of El Ni˜ no Southern Oscillation on stratosphere/troposphere exchange and the global tropospheric ozone budget,
  46. (2005). Influence of El Nin˜o Southern Oscillation on stratosphere/troposphere exchange and the global tropospheric ozone budget,
  47. (2003). Intercontinental transport of air pollution: Will emerging science lead to a new hemispheric treaty?,
  48. (1998). J.-F.: Vertical distributions of lightning NOx for use in regional and global chemical transport models,
  49. (1993). Local versus nonlocal boundary layer diffusion in a global climate model,
  50. (1997). Mass fluxes of O3, CH4, N2O and CF2Cl2 in the lower stratosphere calculated from observational data,
  51. (1997). Model study of cross-tropopause
  52. (2006). Multi-model ensemble simulations of present-day and nearfuture tropospheric ozone,
  53. Nitrogen and sulfur deposition on regional and global scales: A multimodel evaluation,
  54. (1999). On the background photochemistry of tropospheric ozone,
  55. (1995). Ozone chemistry changes in the troposphere and consequent radiative forcing of climate, in: Atmospheric Ozone as a Climate Gas, edited by: Wang,
  56. (1989). Parameterization of surface resistances to gaseous dry deposition in regional-scale numerical models,
  57. (2003). Preindustrial to present day radiative forcing by tropospheric ozone from improved simulations with the GISS chemistry-climate GCM,
  58. (2006). Radiative effect of clouds on tropospheric chemistry in a global threedimensional chemical transport model,
  59. (2000). Radiative forcing from aircraft NOx emissions: Mechanisms and seasonal dependence,
  60. (1999). Radiative forcing from tropospheric ozone calculated with a unified chemistry-climate model,
  61. (2003). Radiative forcing in the 21st century due to ozone changes in the troposphere and lower stratosphere,
  62. (2004). Sensitivities in global scale modeling of isoprene,
  63. (2007). Sensitivities in modelling global tropospheric ozone
  64. (2001). Simulation of tropospheric ozone changes during 1997–1998 El Ni˜ no: Meteorological impact on tropospheric photochemistry,
  65. (2001). Simulation of tropospheric ozone changes during 1997–1998 El Nin˜o: Meteorological impact on tropospheric photochemistry,
  66. (2000). Stratospheric ozone in 3-D models: A simple chemistry and the cross-tropopause flux,
  67. (1940). The balance of effects of deep convective mixing on tropospheric ozone,
  68. (2005). The effects of lightning-produced NOx and its vertical distribution on atmospheric chemistry: sensitivity simulations with MATCHMPIC,
  69. The global atmospheric environment for the next generation,
  70. (1997). The global impact of human activity on tropospheric ozone,
  71. (1990). The impact of air pollutant and methane emission controls on tropospheric ozone and radiative forcing: CTM calculations for the period
  72. (1998). The impact of nonmethane hydrocarbon compounds on tropospheric photochemistry,
  73. (2004). Trans-Eurasian transport of ozone and its precursors,
  74. (2000). Tropospheric ozone simulation with a chemistry-general circulation model: Influence of higher hydrocarbon chemistry,
  75. (1998). Vertical distributions of lightning NOx for use in regional and global chemical transport models,
  76. (2000). What controls tropospheric ozone?
  77. (2007). Why are there large differences between models in global budgets of tropospheric ozone?,
  78. (2007). www.atmos-chem-phys.net/7/2643/2007/ O. Wild: Sensitivities in modelling global tropospheric ozone 2659
  79. (2007). www.atmos-chem-phys.net/7/2643/2007/O. Wild: Sensitivities in modelling global tropospheric ozone 2659

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.