Effect of sulfate aerosol on tropospheric NOx and ozone budgets: Model simulations and TOPSE evidence

	Become an AGU Member Subscribe to AGU Journals



Read Full Article (file size: 6020978 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. D4, 8364, doi:10.1029/2001JD001508, 2003 Effect of sulfate aerosol on tropospheric NO_x and ozone budgets: Model simulations and TOPSE evidence Xuexi Tie National Center for Atmospheric Research, Boulder, Colorado, USA Louisa Emmons National Center for Atmospheric Research, Boulder, Colorado, USA Larry Horowitz NOAA/GFDL, Princeton University, Princeton, New Jersey, USA Guy Brasseur Max-Planck Institute of Meteorology, Hamburg, Germany Brian Ridley National Center for Atmospheric Research, Boulder, Colorado, USA Elliot Atlas National Center for Atmospheric Research, Boulder, Colorado, USA Craig Stround National Center for Atmospheric Research, Boulder, Colorado, USA Peter Hess National Center for Atmospheric Research, Boulder, Colorado, USA Andrzej Klonecki National Center for Atmospheric Research, Boulder, Colorado, USA Sasha Madronich National Center for Atmospheric Research, Boulder, Colorado, USA Robert Talbot Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire, USA Jack Dibb Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire, USA Abstract The distributions of NO_x and O₃ are analyzed during TOPSE (Tropospheric Ozone Production about the Spring Equinox). In this study these data are compared with the calculations of a global chemical/transport model (Model for OZone And Related chemical Tracers (MOZART)). Specifically, the effect that hydrolysis of N₂O₅ on sulfate aerosols has on tropospheric NO_x and O₃ budgets is studied. The results show that without this heterogeneous reaction, the model significantly overestimates NO_x concentrations at high latitudes of the Northern Hemisphere (NH) in winter and spring in comparison to the observations during TOPSE; with this reaction, modeled NO_x concentrations are close to the measured values. This comparison provides evidence that the hydrolysis of N₂O₅ on sulfate aerosol plays an important role in controlling the tropospheric NO_x and O₃ budgets. The calculated reduction of NO_x attributed to this reaction is 80 to 90% in winter at high latitudes over North America. Because of the reduction of NO_x, O₃ concentrations are also decreased. The maximum O₃ reduction occurs in spring although the maximum NO_x reduction occurs in winter when photochemical O₃ production is relatively low. The uncertainties related to uptake coefficient and aerosol loading in the model is analyzed. The analysis indicates that the changes in NO_x due to these uncertainties are much smaller than the impact of hydrolysis of N₂O₅ on sulfate aerosol. The effect that hydrolysis of N₂O₅ on global NO_x and O₃ budgets are also assessed by the model. The results suggest that in the Northern Hemisphere, the average NO_x budget decreases 50% due to this reaction in winter and 5% in summer. The average O₃ budget is reduced by 8% in winter and 6% in summer. In the Southern Hemisphere (SH), the sulfate aerosol loading is significantly smaller than in the Northern Hemisphere. As a result, sulfate aerosol has little impact on NO_x and O₃ budgets of the Southern Hemisphere. Published 13 February 2003. Index Terms: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; 0368 Atmospheric Composition and Structure: Troposphere—constituent transport and chemistry. Read Full Article (file size: 6020978 bytes) Cited by Citation: Tie, X., et al. (2003), Effect of sulfate aerosol on tropospheric NO_x and ozone budgets: Model simulations and TOPSE evidence, J. Geophys. Res., 108(D4), 8364, doi:10.1029/2001JD001508. Copyright 2003 by the American Geophysical Union.

Abstract